/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module org.eclipse.swt.custom.StyledText;


import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.accessibility.ACC;
import org.eclipse.swt.accessibility.Accessible;
import org.eclipse.swt.accessibility.AccessibleAdapter;
import org.eclipse.swt.accessibility.AccessibleControlAdapter;
import org.eclipse.swt.accessibility.AccessibleControlEvent;
import org.eclipse.swt.accessibility.AccessibleEvent;
import org.eclipse.swt.accessibility.AccessibleTextAdapter;
import org.eclipse.swt.accessibility.AccessibleTextEvent;
import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.RTFTransfer;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.events.VerifyListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.GlyphMetrics;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Device;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Resource;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.internal.BidiUtil;
import org.eclipse.swt.internal.Compatibility;
import org.eclipse.swt.printing.Printer;
import org.eclipse.swt.printing.PrinterData;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Caret;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.IME;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.TypedListener;
import org.eclipse.swt.custom.StyledTextContent;
import org.eclipse.swt.custom.TextChangeListener;
import org.eclipse.swt.custom.StyledTextRenderer;
import org.eclipse.swt.custom.StyledTextPrintOptions;
import org.eclipse.swt.custom.ExtendedModifyListener;
import org.eclipse.swt.custom.BidiSegmentListener;
import org.eclipse.swt.custom.LineBackgroundListener;
import org.eclipse.swt.custom.LineStyleListener;
import org.eclipse.swt.custom.PaintObjectListener;
import org.eclipse.swt.custom.VerifyKeyListener;
import org.eclipse.swt.custom.MovementListener;
import org.eclipse.swt.custom.Bullet;
import org.eclipse.swt.custom.StyledTextEvent;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.custom.TextChangedEvent;
import org.eclipse.swt.custom.TextChangingEvent;
import org.eclipse.swt.custom.DefaultContent;
import org.eclipse.swt.custom.StyledTextDropTargetEffect;
import org.eclipse.swt.custom.StyledTextListener;
import org.eclipse.swt.custom.ST;
import java.lang.Runnable;

import java.lang.all;

/**
 * A StyledText is an editable user interface object that displays lines
 * of text.  The following style attributes can be defined for the text:
 * <ul>
 * <li>foreground color
 * <li>background color
 * <li>font style (bold, italic, bold-italic, regular)
 * <li>underline
 * <li>strikeout
 * </ul>
 * <p>
 * In addition to text style attributes, the background color of a line may
 * be specified.
 * </p><p>
 * There are two ways to use this widget when specifying text style information.
 * You may use the API that is defined for StyledText or you may define your own
 * LineStyleListener.  If you define your own listener, you will be responsible
 * for maintaining the text style information for the widget.  IMPORTANT: You may
 * not define your own listener and use the StyledText API.  The following
 * StyledText API is not supported if you have defined a LineStyleListener:
 * <ul>
 * <li>getStyleRangeAtOffset(int)
 * <li>getStyleRanges()
 * <li>replaceStyleRanges(int,int,StyleRange[])
 * <li>setStyleRange(StyleRange)
 * <li>setStyleRanges(StyleRange[])
 * </ul>
 * </p><p>
 * There are two ways to use this widget when specifying line background colors.
 * You may use the API that is defined for StyledText or you may define your own
 * LineBackgroundListener.  If you define your own listener, you will be responsible
 * for maintaining the line background color information for the widget.
 * IMPORTANT: You may not define your own listener and use the StyledText API.
 * The following StyledText API is not supported if you have defined a
 * LineBackgroundListener:
 * <ul>
 * <li>getLineBackground(int)
 * <li>setLineBackground(int,int,Color)
 * </ul>
 * </p><p>
 * The content implementation for this widget may also be user-defined.  To do so,
 * you must implement the StyledTextContent interface and use the StyledText API
 * setContent(StyledTextContent) to initialize the widget.
 * </p><p>
 * <dl>
 * <dt><b>Styles:</b><dd>FULL_SELECTION, MULTI, READ_ONLY, SINGLE, WRAP
 * <dt><b>Events:</b><dd>ExtendedModify, LineGetBackground, LineGetSegments, LineGetStyle, Modify, Selection, Verify, VerifyKey
 * </dl>
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#styledtext">StyledText snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Examples: CustomControlExample, TextEditor</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class StyledText : Canvas {
    alias Canvas.computeSize computeSize;

    static const char TAB = '\t';
    static const String PlatformLineDelimiter = "\r\n";
    static const int BIDI_CARET_WIDTH = 3;
    static const int DEFAULT_WIDTH  = 64;
    static const int DEFAULT_HEIGHT = 64;
    static const int V_SCROLL_RATE = 50;
    static const int H_SCROLL_RATE = 10;

    static const int ExtendedModify = 3000;
    static const int LineGetBackground = 3001;
    static const int LineGetStyle = 3002;
    static const int TextChanging = 3003;
    static const int TextSet = 3004;
    static const int VerifyKey = 3005;
    static const int TextChanged = 3006;
    static const int LineGetSegments = 3007;
    static const int PaintObject = 3008;
    static const int WordNext = 3009;
    static const int WordPrevious = 3010;

    static const int PREVIOUS_OFFSET_TRAILING = 0;
    static const int OFFSET_LEADING = 1;

    Color selectionBackground;  // selection background color
    Color selectionForeground;  // selection foreground color
    StyledTextContent content;          // native content (default or user specified)
    StyledTextRenderer renderer;
    Listener listener;
    TextChangeListener textChangeListener;  // listener for TextChanging, TextChanged and TextSet events from StyledTextContent
    int verticalScrollOffset = 0;       // pixel based
    int horizontalScrollOffset = 0;     // pixel based
    int topIndex = 0;                   // top visible line
    int topIndexY;
    int clientAreaHeight = 0;           // the client area height. Needed to calculate content width for new visible lines during Resize callback
    int clientAreaWidth = 0;            // the client area width. Needed during Resize callback to determine if line wrap needs to be recalculated
    int tabLength = 4;                  // number of characters in a tab
    int leftMargin;
    int topMargin;
    int rightMargin;
    int bottomMargin;
    int columnX;                        // keep track of the horizontal caret position when changing lines/pages. Fixes bug 5935
    int caretOffset = 0;
    int caretAlignment;
    Point selection;                    // x and y are start and end caret offsets of selection
    Point clipboardSelection;           // x and y are start and end caret offsets of previous selection
    int selectionAnchor;                // position of selection anchor. 0 based offset from beginning of text
    Point doubleClickSelection;         // selection after last mouse double click
    bool editable = true;
    bool wordWrap = false;
    bool doubleClickEnabled = true;  // see getDoubleClickEnabled
    bool overwrite = false;          // insert/overwrite edit mode
    int textLimit = -1;                 // limits the number of characters the user can type in the widget. Unlimited by default.
    int[int] keyActionMap;
    Color background = null;            // workaround for bug 4791
    Color foreground = null;            //
    Clipboard clipboard;
    int clickCount;
    int autoScrollDirection = SWT.NULL; // the direction of autoscrolling (up, down, right, left)
    int autoScrollDistance = 0;
    int lastTextChangeStart;            // cache data of the
    int lastTextChangeNewLineCount;     // last text changing
    int lastTextChangeNewCharCount;     // event for use in the
    int lastTextChangeReplaceLineCount; // text changed handler
    int lastTextChangeReplaceCharCount;
    int lastLineBottom;                 // the bottom pixel of the last line been replaced
    bool isMirrored_;
    bool bidiColoring = false;       // apply the BIDI algorithm on text segments of the same color
    Image leftCaretBitmap = null;
    Image rightCaretBitmap = null;
    int caretDirection = SWT.NULL;
    int caretWidth = 0;
    Caret defaultCaret = null;
    bool updateCaretDirection = true;
    bool fixedLineHeight;
    bool dragDetect_ = true;
    IME ime;

    int alignment;
    bool justify;
    int indent;
    int lineSpacing;

    const static bool IS_CARBON, IS_GTK, IS_MOTIF;
    static this(){
        String platform = SWT.getPlatform();
        IS_CARBON = ("carbon" == platform);
        IS_GTK    = ("gtk"    == platform);
        IS_MOTIF  = ("motif"  == platform);
    }

    /**
     * The Printing class : printing of a range of text.
     * An instance of <code>Printing</code> is returned in the
     * StyledText#print(Printer) API. The run() method may be
     * invoked from any thread.
     */
    static class Printing : Runnable {
        const static int LEFT = 0;                      // left aligned header/footer segment
        const static int CENTER = 1;                    // centered header/footer segment
        const static int RIGHT = 2;                     // right aligned header/footer segment

        Printer printer;
        StyledTextRenderer printerRenderer;
        StyledTextPrintOptions printOptions;
        Rectangle clientArea;
        FontData fontData;
        Font printerFont;
        Resource[Resource] resources;
        int tabLength;
        GC gc;                                          // printer GC
        int pageWidth;                                  // width of a printer page in pixels
        int startPage;                                  // first page to print
        int endPage;                                    // last page to print
        int startLine;                                  // first (wrapped) line to print
        int endLine;                                    // last (wrapped) line to print
        bool singleLine;                             // widget single line mode
        Point selection = null;                 // selected text
        bool mirrored;                       // indicates the printing gc should be mirrored
        int lineSpacing;
        int printMargin;

    /**
     * Creates an instance of <code>Printing</code>.
     * Copies the widget content and rendering data that needs
     * to be requested from listeners.
     * </p>
     * @param parent StyledText widget to print.
     * @param printer printer device to print on.
     * @param printOptions print options
     */
    this(StyledText styledText, Printer printer, StyledTextPrintOptions printOptions) {
        this.printer = printer;
        this.printOptions = printOptions;
        this.mirrored = (styledText.getStyle() & SWT.MIRRORED) !is 0;
        singleLine = styledText.isSingleLine();
        startPage = 1;
        endPage = int.max;
        PrinterData data = printer.getPrinterData();
        if (data.scope_ is PrinterData.PAGE_RANGE) {
            startPage = data.startPage;
            endPage = data.endPage;
            if (endPage < startPage) {
                int temp = endPage;
                endPage = startPage;
                startPage = temp;
            }
        } else if (data.scope_ is PrinterData.SELECTION) {
            selection = styledText.getSelectionRange();
        }
        printerRenderer = new StyledTextRenderer(printer, null);
        printerRenderer.setContent(copyContent(styledText.getContent()));
        cacheLineData(styledText);
    }
    /**
     * Caches all line data that needs to be requested from a listener.
     * </p>
     * @param printerContent <code>StyledTextContent</code> to request
     *  line data for.
     */
    void cacheLineData(StyledText styledText) {
        StyledTextRenderer renderer = styledText.renderer;
        renderer.copyInto(printerRenderer);
        fontData = styledText.getFont().getFontData()[0];
        tabLength = styledText.tabLength;
        int lineCount = printerRenderer.lineCount;
        if (styledText.isListening(LineGetBackground) || (styledText.isBidi() && styledText.isListening(LineGetSegments)) || styledText.isListening(LineGetStyle)) {
            StyledTextContent content = printerRenderer.content;
            for (int i = 0; i < lineCount; i++) {
                String line = content.getLine(i);
                int lineOffset = content.getOffsetAtLine(i);
                StyledTextEvent event = styledText.getLineBackgroundData(lineOffset, line);
                if (event !is null && event.lineBackground !is null) {
                    printerRenderer.setLineBackground(i, 1, event.lineBackground);
                }
                if (styledText.isBidi()) {
                    int[] segments = styledText.getBidiSegments(lineOffset, line);
                    printerRenderer.setLineSegments(i, 1, segments);
                }
                event = styledText.getLineStyleData(lineOffset, line);
                if (event !is null) {
                    printerRenderer.setLineIndent(i, 1, event.indent);
                    printerRenderer.setLineAlignment(i, 1, event.alignment);
                    printerRenderer.setLineJustify(i, 1, event.justify);
                    printerRenderer.setLineBullet(i, 1, event.bullet);
                    StyleRange[] styles = event.styles;
                    if (styles !is null && styles.length > 0) {
                        printerRenderer.setStyleRanges(event.ranges, styles);
                    }
                }
            }
        }
        Point screenDPI = styledText.getDisplay().getDPI();
        Point printerDPI = printer.getDPI();
        resources = null;
        for (int i = 0; i < lineCount; i++) {
            Color color = printerRenderer.getLineBackground(i, null);
            if (color !is null) {
                if (printOptions.printLineBackground) {
                    Color printerColor;
                    if ( auto p = color in resources ) {
                        printerColor = cast(Color)*p;
                    }
                    else {
                        printerColor = new Color (printer, color.getRGB());
                        resources[color]=printerColor;
                    }
                    printerRenderer.setLineBackground(i, 1, printerColor);
                } else {
                    printerRenderer.setLineBackground(i, 1, null);
                }
            }
            int indent = printerRenderer.getLineIndent(i, 0);
            if (indent !is 0) {
                printerRenderer.setLineIndent(i, 1, indent * printerDPI.x / screenDPI.x);
            }
        }
        StyleRange[] styles = printerRenderer.styles;
        for (int i = 0; i < printerRenderer.styleCount; i++) {
            StyleRange style = styles[i];
            Font font = style.font;
            if (style.font !is null) {
                Font printerFont;
                if ( auto p = font in resources ) {
                    printerFont = cast(Font)*p;
                }
                else {
                    printerFont = new Font (printer, font.getFontData());
                    resources[font]= printerFont;
                }
                style.font = printerFont;
            }
            Color color = style.foreground;
            if (color !is null) {
                if (printOptions.printTextForeground) {
                    Color printerColor;
                    if ( auto p = color in resources ) {
                        printerColor = cast(Color)*p;
                    }
                    else {
                        printerColor = new Color (printer, color.getRGB());
                        resources[color]=printerColor;
                    }
                    style.foreground = printerColor;
                } else {
                    style.foreground = null;
                }
            }
            color = style.background;
            if (color !is null) {
                if (printOptions.printTextBackground) {
                    Color printerColor;
                    if ( auto p = color in resources ) {
                        printerColor = cast(Color)*p;
                    }
                    else {
                        printerColor = new Color (printer, color.getRGB());
                        resources[color]=printerColor;
                    }
                    style.background = printerColor;
                } else {
                    style.background = null;
                }
            }
            if (!printOptions.printTextFontStyle) {
                style.fontStyle = SWT.NORMAL;
            }
            style.rise = style.rise * printerDPI.y / screenDPI.y;
            GlyphMetrics metrics = style.metrics;
            if (metrics !is null) {
                metrics.ascent = metrics.ascent * printerDPI.y / screenDPI.y;
                metrics.descent = metrics.descent * printerDPI.y / screenDPI.y;
                metrics.width = metrics.width * printerDPI.x / screenDPI.x;
            }
        }
        lineSpacing = styledText.lineSpacing * printerDPI.y / screenDPI.y;
        if (printOptions.printLineNumbers) {
            printMargin = 3 * printerDPI.x / screenDPI.x;
        }
    }
    /**
     * Copies the text of the specified <code>StyledTextContent</code>.
     * </p>
     * @param original the <code>StyledTextContent</code> to copy.
     */
    StyledTextContent copyContent(StyledTextContent original) {
        StyledTextContent printerContent = new DefaultContent();
        int insertOffset = 0;
        for (int i = 0; i < original.getLineCount(); i++) {
            int insertEndOffset;
            if (i < original.getLineCount() - 1) {
                insertEndOffset = original.getOffsetAtLine(i + 1);
            } else {
                insertEndOffset = original.getCharCount();
            }
            printerContent.replaceTextRange(insertOffset, 0, original.getTextRange(insertOffset, insertEndOffset - insertOffset));
            insertOffset = insertEndOffset;
        }
        return printerContent;
    }
    /**
     * Disposes of the resources and the <code>PrintRenderer</code>.
     */
    void dispose() {
        if (gc !is null) {
            gc.dispose();
            gc = null;
        }
        foreach( resource; resources.values ){
            resource.dispose();
        }
        resources = null;
        if (printerFont !is null) {
            printerFont.dispose();
            printerFont = null;
        }
        if (printerRenderer !is null) {
            printerRenderer.dispose();
            printerRenderer = null;
        }
    }
    void init_() {
        Rectangle trim = printer.computeTrim(0, 0, 0, 0);
        Point dpi = printer.getDPI();

        printerFont = new Font( cast(Device)printer, fontData.getName(), fontData.getHeight(), SWT.NORMAL);
        clientArea = printer.getClientArea();
        pageWidth = clientArea.width;
        // one inch margin around text
        clientArea.x = dpi.x + trim.x;
        clientArea.y = dpi.y + trim.y;
        clientArea.width -= (clientArea.x + trim.width);
        clientArea.height -= (clientArea.y + trim.height);

        int style = mirrored ? SWT.RIGHT_TO_LEFT : SWT.LEFT_TO_RIGHT;
        gc = new GC(printer, style);
        gc.setFont(printerFont);
        printerRenderer.setFont(printerFont, tabLength);
        int lineHeight = printerRenderer.getLineHeight();
        if (printOptions.header !is null) {
            clientArea.y += lineHeight * 2;
            clientArea.height -= lineHeight * 2;
        }
        if (printOptions.footer !is null) {
            clientArea.height -= lineHeight * 2;
        }

        // TODO not wrapped
        StyledTextContent content = printerRenderer.content;
        startLine = 0;
        endLine = singleLine ? 0 : content.getLineCount() - 1;
        PrinterData data = printer.getPrinterData();
        if (data.scope_ is PrinterData.PAGE_RANGE) {
            int pageSize = clientArea.height / lineHeight;//WRONG
            startLine = (startPage - 1) * pageSize;
        } else if (data.scope_ is PrinterData.SELECTION) {
            startLine = content.getLineAtOffset(selection.x);
            if (selection.y > 0) {
                endLine = content.getLineAtOffset(selection.x + selection.y - 1);
            } else {
                endLine = startLine - 1;
            }
        }
    }
    /**
     * Prints the lines in the specified page range.
     */
    void print() {
        Color background = gc.getBackground();
        Color foreground = gc.getForeground();
        int paintY = clientArea.y;
        int paintX = clientArea.x;
        int width = clientArea.width;
        int page = startPage;
        int pageBottom = clientArea.y + clientArea.height;
        int orientation =  gc.getStyle() & (SWT.RIGHT_TO_LEFT | SWT.LEFT_TO_RIGHT);
        TextLayout printLayout = null;
        if (printOptions.printLineNumbers || printOptions.header !is null || printOptions.footer !is null) {
            printLayout = new TextLayout(printer);
            printLayout.setFont(printerFont);
        }
        if (printOptions.printLineNumbers) {
            int numberingWidth = 0;
            int count = endLine - startLine + 1;
            String[] lineLabels = printOptions.lineLabels;
            if (lineLabels !is null) {
                for (int i = startLine; i < Math.min(count, lineLabels.length); i++) {
                    if (lineLabels[i] !is null) {
                        printLayout.setText(lineLabels[i]);
                        int lineWidth = printLayout.getBounds().width;
                        numberingWidth = Math.max(numberingWidth, lineWidth);
                    }
                }
            } else {
                StringBuffer buffer = new StringBuffer("0");
                while ((count /= 10) > 0) buffer.append("0");
                printLayout.setText(buffer.toString());
                numberingWidth = printLayout.getBounds().width;
            }
            numberingWidth += printMargin;
            if (numberingWidth > width) numberingWidth = width;
            paintX += numberingWidth;
            width -= numberingWidth;
        }
        for (int i = startLine; i <= endLine && page <= endPage; i++) {
            if (paintY is clientArea.y) {
                printer.startPage();
                printDecoration(page, true, printLayout);
            }
            TextLayout layout = printerRenderer.getTextLayout(i, orientation, width, lineSpacing);
            Color lineBackground = printerRenderer.getLineBackground(i, background);
            int paragraphBottom = paintY + layout.getBounds().height;
            if (paragraphBottom <= pageBottom) {
                //normal case, the whole paragraph fits in the current page
                printLine(paintX, paintY, gc, foreground, lineBackground, layout, printLayout, i);
                paintY = paragraphBottom;
            } else {
                int lineCount = layout.getLineCount();
                while (paragraphBottom > pageBottom && lineCount > 0) {
                    lineCount--;
                    paragraphBottom -= layout.getLineBounds(lineCount).height + layout.getSpacing();
                }
                if (lineCount is 0) {
                    //the whole paragraph goes to the next page
                    printDecoration(page, false, printLayout);
                    printer.endPage();
                    page++;
                    if (page <= endPage) {
                        printer.startPage();
                        printDecoration(page, true, printLayout);
                        paintY = clientArea.y;
                        printLine(paintX, paintY, gc, foreground, lineBackground, layout, printLayout, i);
                        paintY += layout.getBounds().height;
                    }
                } else {
                    //draw paragraph top in the current page and paragraph bottom in the next
                    int height = paragraphBottom - paintY;
                    gc.setClipping(clientArea.x, paintY, clientArea.width, height);
                    printLine(paintX, paintY, gc, foreground, lineBackground, layout, printLayout, i);
                    gc.setClipping(cast(Rectangle)null);
                    printDecoration(page, false, printLayout);
                    printer.endPage();
                    page++;
                    if (page <= endPage) {
                        printer.startPage();
                        printDecoration(page, true, printLayout);
                        paintY = clientArea.y - height;
                        int layoutHeight = layout.getBounds().height;
                        gc.setClipping(clientArea.x, clientArea.y, clientArea.width, layoutHeight - height);
                        printLine(paintX, paintY, gc, foreground, lineBackground, layout, printLayout, i);
                        gc.setClipping(cast(Rectangle)null);
                        paintY += layoutHeight;
                    }
                }
            }
            printerRenderer.disposeTextLayout(layout);
        }
        if (page <= endPage && paintY > clientArea.y) {
            // close partial page
            printDecoration(page, false, printLayout);
            printer.endPage();
        }
        if (printLayout !is null) printLayout.dispose();
    }
    /**
     * Print header or footer decorations.
     *
     * @param page page number to print, if specified in the StyledTextPrintOptions header or footer.
     * @param header true = print the header, false = print the footer
     */
    void printDecoration(int page, bool header, TextLayout layout) {
        String text = header ? printOptions.header : printOptions.footer;
        if (text is null) return;
        int lastSegmentIndex = 0;
        for (int i = 0; i < 3; i++) {
            int segmentIndex = text.indexOf( StyledTextPrintOptions.SEPARATOR, lastSegmentIndex);
            String segment;
            if (segmentIndex is -1 ) {
                segment = text.substring(lastSegmentIndex);
                printDecorationSegment(segment, i, page, header, layout);
                break;
            } else {
                segment = text.substring(lastSegmentIndex, segmentIndex);
                printDecorationSegment(segment, i, page, header, layout);
                lastSegmentIndex = segmentIndex + StyledTextPrintOptions.SEPARATOR.length;
            }
        }
    }
    /**
     * Print one segment of a header or footer decoration.
     * Headers and footers have three different segments.
     * One each for left aligned, centered, and right aligned text.
     *
     * @param segment decoration segment to print
     * @param alignment alignment of the segment. 0=left, 1=center, 2=right
     * @param page page number to print, if specified in the decoration segment.
     * @param header true = print the header, false = print the footer
     */
    void printDecorationSegment(String segment, int alignment, int page, bool header, TextLayout layout) {
        int pageIndex = segment.indexOf(StyledTextPrintOptions.PAGE_TAG);
        if (pageIndex !is -1 ) {
            int pageTagLength = StyledTextPrintOptions.PAGE_TAG.length;
            StringBuffer buffer = new StringBuffer(segment.substring (0, pageIndex));
            buffer.append (page);
            buffer.append (segment.substring(pageIndex + pageTagLength));
            segment = buffer.toString()._idup();
        }
        if (segment.length > 0) {
            layout.setText(segment);
            int segmentWidth = layout.getBounds().width;
            int segmentHeight = printerRenderer.getLineHeight();
            int drawX = 0, drawY;
            if (alignment is LEFT) {
                drawX = clientArea.x;
            } else if (alignment is CENTER) {
                drawX = (pageWidth - segmentWidth) / 2;
            } else if (alignment is RIGHT) {
                drawX = clientArea.x + clientArea.width - segmentWidth;
            }
            if (header) {
                drawY = clientArea.y - segmentHeight * 2;
            } else {
                drawY = clientArea.y + clientArea.height + segmentHeight;
            }
            layout.draw(gc, drawX, drawY);
        }
    }
    void printLine(int x, int y, GC gc, Color foreground, Color background, TextLayout layout, TextLayout printLayout, int index) {
        if (background !is null) {
            Rectangle rect = layout.getBounds();
            gc.setBackground(background);
            gc.fillRectangle(x, y, rect.width, rect.height);

//          int lineCount = layout.getLineCount();
//          for (int i = 0; i < lineCount; i++) {
//              Rectangle rect = layout.getLineBounds(i);
//              rect.x += paintX;
//              rect.y += paintY + layout.getSpacing();
//              rect.width = width;//layout bounds
//              gc.fillRectangle(rect);
//          }
        }
        if (printOptions.printLineNumbers) {
            FontMetrics metrics = layout.getLineMetrics(0);
            printLayout.setAscent(metrics.getAscent() + metrics.getLeading());
            printLayout.setDescent(metrics.getDescent());
            String[] lineLabels = printOptions.lineLabels;
            if (lineLabels !is null) {
                if (0 <= index && index < lineLabels.length && lineLabels[index] !is null) {
                    printLayout.setText(lineLabels[index]);
                } else {
                    printLayout.setText("");
                }
            } else {
                printLayout.setText(String_valueOf(index));
            }
            int paintX = x - printMargin - printLayout.getBounds().width;
            printLayout.draw(gc, paintX, y);
            printLayout.setAscent(-1);
            printLayout.setDescent(-1);
        }
        gc.setForeground(foreground);
        layout.draw(gc, x, y);
    }
    /**
     * Starts a print job and prints the pages specified in the constructor.
     */
    public void run() {
        String jobName = printOptions.jobName;
        if (jobName is null) {
            jobName = "Printing";
        }
        if (printer.startJob(jobName)) {
            init_();
            print();
            dispose();
            printer.endJob();
        }
    }
    }
    /**
     * The <code>RTFWriter</code> class is used to write widget content as
     * rich text. The implementation complies with the RTF specification
     * version 1.5.
     * <p>
     * toString() is guaranteed to return a valid RTF string only after
     * close() has been called.
     * </p><p>
     * Whole and partial lines and line breaks can be written. Lines will be
     * formatted using the styles queried from the LineStyleListener, if
     * set, or those set directly in the widget. All styles are applied to
     * the RTF stream like they are rendered by the widget. In addition, the
     * widget font name and size is used for the whole text.
     * </p>
     */
    class RTFWriter : TextWriter {

        alias TextWriter.write write;

        static const int DEFAULT_FOREGROUND = 0;
        static const int DEFAULT_BACKGROUND = 1;
        Color[] colorTable;
        Font[] fontTable;
        bool WriteUnicode;

    /**
     * Creates a RTF writer that writes content starting at offset "start"
     * in the document.  <code>start</code> and <code>length</code>can be set to specify partial
     * lines.
     *
     * @param start start offset of content to write, 0 based from
     *  beginning of document
     * @param length length of content to write
     */
    public this(int start, int length) {
        super(start, length);
        colorTable ~= getForeground();
        colorTable ~= getBackground();
        fontTable ~= getFont();
        setUnicode();
    }
    /**
     * Closes the RTF writer. Once closed no more content can be written.
     * <b>NOTE:</b>  <code>toString()</code> does not return a valid RTF string until
     * <code>close()</code> has been called.
     */
    public override void close() {
        if (!isClosed()) {
            writeHeader();
            write("\n}}\0");
            super.close();
        }
    }
    /**
     * Returns the index of the specified color in the RTF color table.
     *
     * @param color the color
     * @param defaultIndex return value if color is null
     * @return the index of the specified color in the RTF color table
     *  or "defaultIndex" if "color" is null.
     */
    int getColorIndex(Color color, int defaultIndex) {
        if (color is null) return defaultIndex;
        int index = -1;
        foreach( i, col; colorTable ){
            if( col == color ){
                index = i;
                break;
            }
        }
        if (index is -1) {
            index = colorTable.length;
            colorTable ~= color;
        }
        return index;
    }
    /**
     * Returns the index of the specified color in the RTF color table.
     *
     * @param color the color
     * @param defaultIndex return value if color is null
     * @return the index of the specified color in the RTF color table
     *  or "defaultIndex" if "color" is null.
     */
    int getFontIndex(Font font) {
        int index = -1;
        foreach( i, f; colorTable ){
            if( f == font ){
                index = i;
                break;
            }
        }
        if (index is -1) {
            index = fontTable.length;
            fontTable ~= font;
        }
        return index;
    }
    /**
     * Determines if Unicode RTF should be written.
     * Don't write Unicode RTF on Windows 95/98/ME or NT.
     */
    void setUnicode() {
//         const String Win95 = "windows 95";
//         const String Win98 = "windows 98";
//         const String WinME = "windows me";
//         const String WinNT = "windows nt";
//         String osName = System.getProperty("os.name").toLowerCase();
//         String osVersion = System.getProperty("os.version");
//         int majorVersion = 0;
//
//         if (osName.startsWith(WinNT) && osVersion !is null) {
//             int majorIndex = osVersion.indexOf('.');
//             if (majorIndex !is -1) {
//                 osVersion = osVersion.substring(0, majorIndex);
//                 try {
//                     majorVersion = Integer.parseInt(osVersion);
//                 } catch (NumberFormatException exception) {
//                     // ignore exception. version number remains unknown.
//                     // will write without Unicode
//                 }
//             }
//         }
//         WriteUnicode =  !osName.startsWith(Win95) &&
//                         !osName.startsWith(Win98) &&
//                         !osName.startsWith(WinME) &&
//                         (!osName.startsWith(WinNT) || majorVersion > 4);
        WriteUnicode = true; // we are on linux-gtk
    }
    /**
     * Appends the specified segment of "string" to the RTF data.
     * Copy from <code>start</code> up to, but excluding, <code>end</code>.
     *
     * @param string string to copy a segment from. Must not contain
     *  line breaks. Line breaks should be written using writeLineDelimiter()
     * @param start start offset of segment. 0 based.
     * @param end end offset of segment
     */
    void write(String string, int start, int end) {
        start = 0;
        end = string.length;
        int incr = 1;
        for (int index = start; index < end; index+=incr) {
            dchar ch = firstCodePoint( string[index .. $], incr );
            if (ch > 0xFF && WriteUnicode) {
                // write the sub string from the last escaped character
                // to the current one. Fixes bug 21698.
                if (index > start) {
                    write( string[start .. index ] );
                }
                write("\\u");
                write( String_valueOf( cast(short)ch ));
                write(' ');                     // control word delimiter
                start = index + incr;
            } else if (ch is '}' || ch is '{' || ch is '\\') {
                // write the sub string from the last escaped character
                // to the current one. Fixes bug 21698.
                if (index > start) {
                    write(string[start .. index]);
                }
                write('\\');
                write(cast(char)ch); // ok because one of {}\
                start = index + 1;
            }
        }
        // write from the last escaped character to the end.
        // Fixes bug 21698.
        if (start < end) {
            write(string[ start .. end]);
        }
    }
    /**
     * Writes the RTF header including font table and color table.
     */
    void writeHeader() {
        StringBuffer header = new StringBuffer();
        FontData fontData = getFont().getFontData()[0];
        header.append("{\\rtf1\\ansi");
        // specify code page, necessary for copy to work in bidi
        // systems that don't support Unicode RTF.
        // PORTING_TODO: String cpg = System.getProperty("file.encoding").toLowerCase();
        String cpg = "UTF16";
        /+
        if (cpg.startsWith("cp") || cpg.startsWith("ms")) {
            cpg = cpg.substring(2, cpg.length());
            header.append("\\ansicpg");
            header.append(cpg);
        }
        +/
        header.append("\\uc0\\deff0{\\fonttbl{\\f0\\fnil ");
        header.append(fontData.getName());
        header.append(";");
        for (int i = 1; i < fontTable.length; i++) {
            header.append("\\f");
            header.append(i);
            header.append(" ");
            FontData fd = (cast(Font)fontTable[i]).getFontData()[0];
            header.append(fd.getName());
            header.append(";");
        }
        header.append("}}\n{\\colortbl");
        for (int i = 0; i < colorTable.length; i++) {
            Color color = cast(Color) colorTable[i];
            header.append("\\red");
            header.append(color.getRed());
            header.append("\\green");
            header.append(color.getGreen());
            header.append("\\blue");
            header.append(color.getBlue());
            header.append(";");
        }
        // some RTF readers ignore the deff0 font tag. Explicitly
        // set the font for the whole document to work around this.
        header.append("}\n{\\f0\\fs");
        // font size is specified in half points
        header.append(fontData.getHeight() * 2);
        header.append(" ");
        write(header.toString(), 0);
    }
    /**
     * Appends the specified line text to the RTF data.  Lines will be formatted
     * using the styles queried from the LineStyleListener, if set, or those set
     * directly in the widget.
     *
     * @param line line text to write as RTF. Must not contain line breaks
     *  Line breaks should be written using writeLineDelimiter()
     * @param lineOffset offset of the line. 0 based from the start of the
     *  widget document. Any text occurring before the start offset or after the
     *  end offset specified during object creation is ignored.
     * @exception SWTException <ul>
     *   <li>ERROR_IO when the writer is closed.</li>
     * </ul>
     */
    public override void writeLine(String line, int lineOffset) {
        if (isClosed()) {
            SWT.error(SWT.ERROR_IO);
        }
        int lineIndex = content.getLineAtOffset(lineOffset);
        int lineAlignment, lineIndent;
        bool lineJustify;
        int[] ranges;
        StyleRange[] styles;
        StyledTextEvent event = getLineStyleData(lineOffset, line);
        if (event !is null) {
            lineAlignment = event.alignment;
            lineIndent = event.indent;
            lineJustify = event.justify;
            ranges = event.ranges;
            styles = event.styles;
        } else {
            lineAlignment = renderer.getLineAlignment(lineIndex, alignment);
            lineIndent =  renderer.getLineIndent(lineIndex, indent);
            lineJustify = renderer.getLineJustify(lineIndex, justify);
            ranges = renderer.getRanges(lineOffset, line.length);
            styles = renderer.getStyleRanges(lineOffset, line.length, false);
        }
        if (styles is null) styles = new StyleRange[0];
        Color lineBackground = renderer.getLineBackground(lineIndex, null);
        event = getLineBackgroundData(lineOffset, line);
        if (event !is null && event.lineBackground !is null) lineBackground = event.lineBackground;
        writeStyledLine(line, lineOffset, ranges, styles, lineBackground, lineIndent, lineAlignment, lineJustify);
    }
    /**
     * Appends the specified line delimiter to the RTF data.
     *
     * @param lineDelimiter line delimiter to write as RTF.
     * @exception SWTException <ul>
     *   <li>ERROR_IO when the writer is closed.</li>
     * </ul>
     */
    public override void writeLineDelimiter(String lineDelimiter) {
        if (isClosed()) {
            SWT.error(SWT.ERROR_IO);
        }
        write(lineDelimiter, 0, lineDelimiter.length);
        write("\\par ");
    }
    /**
     * Appends the specified line text to the RTF data.
     * <p>
     * Use the colors and font styles specified in "styles" and "lineBackground".
     * Formatting is written to reflect the text rendering by the text widget.
     * Style background colors take precedence over the line background color.
     * Background colors are written using the \highlight tag (vs. the \cb tag).
     * </p>
     *
     * @param line line text to write as RTF. Must not contain line breaks
     *  Line breaks should be written using writeLineDelimiter()
     * @param lineOffset offset of the line. 0 based from the start of the
     *  widget document. Any text occurring before the start offset or after the
     *  end offset specified during object creation is ignored.
     * @param styles styles to use for formatting. Must not be null.
     * @param lineBackground line background color to use for formatting.
     *  May be null.
     */
    void writeStyledLine(String line, int lineOffset, int ranges[], StyleRange[] styles, Color lineBackground, int indent, int alignment, bool justify) {
        int lineLength = line.length;
        int startOffset = getStart();
        int writeOffset = startOffset - lineOffset;
        if (writeOffset >= lineLength) return;
        int lineIndex = Math.max(0, writeOffset);

        write("\\fi");
        write(indent);
        switch (alignment) {
            case SWT.LEFT: write("\\ql"); break;
            case SWT.CENTER: write("\\qc"); break;
            case SWT.RIGHT: write("\\qr"); break;
            default:
        }
        if (justify) write("\\qj");
        write(" ");

        if (lineBackground !is null) {
            write("{\\highlight");
            write(getColorIndex(lineBackground, DEFAULT_BACKGROUND));
            write(" ");
        }
        int endOffset = startOffset + super.getCharCount();
        int lineEndOffset = Math.min(lineLength, endOffset - lineOffset);
        for (int i = 0; i < styles.length; i++) {
            StyleRange style = styles[i];
            int start, end;
            if (ranges !is null) {
                start = ranges[i << 1] - lineOffset;
                end = start + ranges[(i << 1) + 1];
            } else {
                start = style.start - lineOffset;
                end = start + style.length;
            }
            // skip over partial first line
            if (end < writeOffset) {
                continue;
            }
            // style starts beyond line end or RTF write end
            if (start >= lineEndOffset) {
                break;
            }
            // write any unstyled text
            if (lineIndex < start) {
                // copy to start of style
                // style starting beyond end of write range or end of line
                // is guarded against above.
                write(line, lineIndex, start);
                lineIndex = start;
            }
            // write styled text
            write("{\\cf");
            write(getColorIndex(style.foreground, DEFAULT_FOREGROUND));
            int colorIndex = getColorIndex(style.background, DEFAULT_BACKGROUND);
            if (colorIndex !is DEFAULT_BACKGROUND) {
                write("\\highlight");
                write(colorIndex);
            }
            Font font = style.font;
            if (font !is null) {
                int fontIndex = getFontIndex(font);
                write("\\f");
                write(fontIndex);
                FontData fontData = font.getFontData()[0];
                write("\\fs");
                write(fontData.getHeight() * 2);
            } else {
                if ((style.fontStyle & SWT.BOLD) !is 0) {
                    write("\\b");
                }
                if ((style.fontStyle & SWT.ITALIC) !is 0) {
                    write("\\i");
                }
            }
            if (style.underline) {
                write("\\ul");
            }
            if (style.strikeout) {
                write("\\strike");
            }
            write(" ");
            // copy to end of style or end of write range or end of line
            int copyEnd = Math.min(end, lineEndOffset);
            // guard against invalid styles and let style processing continue
            copyEnd = Math.max(copyEnd, lineIndex);
            write(line, lineIndex, copyEnd);
            if (font is null) {
                if ((style.fontStyle & SWT.BOLD) !is 0) {
                    write("\\b0");
                }
                if ((style.fontStyle & SWT.ITALIC) !is 0) {
                    write("\\i0");
                }
            }
            if (style.underline) {
                write("\\ul0");
            }
            if (style.strikeout) {
                write("\\strike0");
            }
            write("}");
            lineIndex = copyEnd;
        }
        // write unstyled text at the end of the line
        if (lineIndex < lineEndOffset) {
            write(line, lineIndex, lineEndOffset);
        }
        if (lineBackground !is null) write("}");
    }
    }
    /**
     * The <code>TextWriter</code> class is used to write widget content to
     * a string.  Whole and partial lines and line breaks can be written. To write
     * partial lines, specify the start and length of the desired segment
     * during object creation.
     * <p>
     * </b>NOTE:</b> <code>toString()</code> is guaranteed to return a valid string only after close()
     * has been called.
     * </p>
     */
    class TextWriter {
        private StringBuffer buffer;
        private int startOffset;    // offset of first character that will be written
        private int endOffset;      // offset of last character that will be written.
                                    // 0 based from the beginning of the widget text.
        private bool isClosed_ = false;

    /**
     * Creates a writer that writes content starting at offset "start"
     * in the document.  <code>start</code> and <code>length</code> can be set to specify partial lines.
     *
     * @param start start offset of content to write, 0 based from beginning of document
     * @param length length of content to write
     */
    public this(int start, int length) {
        buffer = new StringBuffer(length);
        startOffset = start;
        endOffset = start + length;
    }
    /**
     * Closes the writer. Once closed no more content can be written.
     * <b>NOTE:</b>  <code>toString()</code> is not guaranteed to return a valid string unless
     * the writer is closed.
     */
    public void close() {
        if (!isClosed_) {
            isClosed_ = true;
        }
    }
    /**
     * Returns the number of characters to write.
     * @return the integer number of characters to write
     */
    public int getCharCount() {
        return endOffset - startOffset;
    }
    /**
     * Returns the offset where writing starts. 0 based from the start of
     * the widget text. Used to write partial lines.
     * @return the integer offset where writing starts
     */
    public int getStart() {
        return startOffset;
    }
    /**
     * Returns whether the writer is closed.
     * @return a bool specifying whether or not the writer is closed
     */
    public bool isClosed() {
        return isClosed_;
    }
    /**
     * Returns the string.  <code>close()</code> must be called before <code>toString()</code>
     * is guaranteed to return a valid string.
     *
     * @return the string
     */
    public override String toString() {
        return buffer.toString();
    }
    /**
     * Appends the given string to the data.
     */
    void write(String string) {
        buffer.append(string);
    }
    /**
     * Inserts the given string to the data at the specified offset.
     * <p>
     * Do nothing if "offset" is < 0 or > getCharCount()
     * </p>
     *
     * @param string text to insert
     * @param offset offset in the existing data to insert "string" at.
     */
    void write(String string, int offset) {
        if (offset < 0 || offset > buffer.length()) {
            return;
        }
        buffer.insert(offset, string);
    }
    /**
     * Appends the given int to the data.
     */
    void write(int i) {
        buffer.append(i);
    }
    /**
     * Appends the given character to the data.
     */
    void write(char i) {
        buffer.append(i);
    }
    /**
     * Appends the specified line text to the data.
     *
     * @param line line text to write. Must not contain line breaks
     *  Line breaks should be written using writeLineDelimiter()
     * @param lineOffset offset of the line. 0 based from the start of the
     *  widget document. Any text occurring before the start offset or after the
     *  end offset specified during object creation is ignored.
     * @exception SWTException <ul>
     *   <li>ERROR_IO when the writer is closed.</li>
     * </ul>
     */
    public void writeLine(String line, int lineOffset) {
        if (isClosed_) {
            SWT.error(SWT.ERROR_IO);
        }
        int writeOffset = startOffset - lineOffset;
        int lineLength = line.length;
        int lineIndex;
        if (writeOffset >= lineLength) {
            return;                         // whole line is outside write range
        } else if (writeOffset > 0) {
            lineIndex = writeOffset;        // line starts before write start
        } else {
            lineIndex = 0;
        }
        int copyEnd = Math.min(lineLength, endOffset - lineOffset);
        if (lineIndex < copyEnd) {
            write(line.substring(lineIndex, copyEnd));
        }
    }
    /**
     * Appends the specified line delimiter to the data.
     *
     * @param lineDelimiter line delimiter to write
     * @exception SWTException <ul>
     *   <li>ERROR_IO when the writer is closed.</li>
     * </ul>
     */
    public void writeLineDelimiter(String lineDelimiter) {
        if (isClosed_) {
            SWT.error(SWT.ERROR_IO);
        }
        write(lineDelimiter);
    }
    }

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a widget which will be the parent of the new instance (cannot be null)
 * @param style the style of widget to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 * </ul>
 *
 * @see SWT#FULL_SELECTION
 * @see SWT#MULTI
 * @see SWT#READ_ONLY
 * @see SWT#SINGLE
 * @see SWT#WRAP
 * @see #getStyle
 */
public this(Composite parent, int style) {
    selection = new Point(0, 0);
    super(parent, checkStyle(style));
    // set the fg in the OS to ensure that these are the same as StyledText, necessary
    // for ensuring that the bg/fg the IME box uses is the same as what StyledText uses
    super.setForeground(getForeground());
    super.setDragDetect(false);
    Display display = getDisplay();
    isMirrored_ = (super.getStyle() & SWT.MIRRORED) !is 0;
    fixedLineHeight = true;
    if ((style & SWT.READ_ONLY) !is 0) {
        setEditable(false);
    }
    leftMargin = rightMargin = isBidiCaret() ? BIDI_CARET_WIDTH - 1: 0;
    if ((style & SWT.SINGLE) !is 0 && (style & SWT.BORDER) !is 0) {
        leftMargin = topMargin = rightMargin = bottomMargin = 2;
    }
    alignment = style & (SWT.LEFT | SWT.RIGHT | SWT.CENTER);
    if (alignment is 0) alignment = SWT.LEFT;
    clipboard = new Clipboard(display);
    installDefaultContent();
    renderer = new StyledTextRenderer(getDisplay(), this);
    renderer.setContent(content);
    renderer.setFont(getFont(), tabLength);
    ime = new IME(this, SWT.NONE);
    defaultCaret = new Caret(this, SWT.NONE);
    if ((style & SWT.WRAP) !is 0) {
        setWordWrap(true);
    }
    if (isBidiCaret()) {
        createCaretBitmaps();
        Runnable runnable = new class() Runnable {
            public void run() {
                int direction = BidiUtil.getKeyboardLanguage() is BidiUtil.KEYBOARD_BIDI ? SWT.RIGHT : SWT.LEFT;
                if (direction is caretDirection) return;
                if (getCaret() !is defaultCaret) return;
                Point newCaretPos = getPointAtOffset(caretOffset);
                setCaretLocation(newCaretPos, direction);
            }
        };
        BidiUtil.addLanguageListener(this, runnable);
    }
    setCaret(defaultCaret);
    calculateScrollBars();
    createKeyBindings();
    setCursor(display.getSystemCursor(SWT.CURSOR_IBEAM));
    installListeners();
    initializeAccessible();
    setData("DEFAULT_DROP_TARGET_EFFECT", new StyledTextDropTargetEffect(this));
}
/**
 * Adds an extended modify listener. An ExtendedModify event is sent by the
 * widget when the widget text has changed.
 *
 * @param extendedModifyListener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addExtendedModifyListener(ExtendedModifyListener extendedModifyListener) {
    checkWidget();
    if (extendedModifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    StyledTextListener typedListener = new StyledTextListener(extendedModifyListener);
    addListener(ExtendedModify, typedListener);
}
/**
 * Adds a bidirectional segment listener.
 * <p>
 * A BidiSegmentEvent is sent
 * whenever a line of text is measured or rendered. The user can
 * specify text ranges in the line that should be treated as if they
 * had a different direction than the surrounding text.
 * This may be used when adjacent segments of right-to-left text should
 * not be reordered relative to each other.
 * E.g., Multiple Java string literals in a right-to-left language
 * should generally remain in logical order to each other, that is, the
 * way they are stored.
 * </p>
 *
 * @param listener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 * @see BidiSegmentEvent
 * @since 2.0
 */
public void addBidiSegmentListener(BidiSegmentListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(LineGetSegments, new StyledTextListener(listener));
}
/**
 * Adds a line background listener. A LineGetBackground event is sent by the
 * widget to determine the background color for a line.
 *
 * @param listener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addLineBackgroundListener(LineBackgroundListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    if (!isListening(LineGetBackground)) {
        renderer.clearLineBackground(0, content.getLineCount());
    }
    addListener(LineGetBackground, new StyledTextListener(listener));
}
/**
 * Adds a line style listener. A LineGetStyle event is sent by the widget to
 * determine the styles for a line.
 *
 * @param listener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addLineStyleListener(LineStyleListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    if (!isListening(LineGetStyle)) {
        setStyleRanges(0, 0, null, null, true);
        renderer.clearLineStyle(0, content.getLineCount());
    }
    addListener(LineGetStyle, new StyledTextListener(listener));
}
/**
 * Adds a modify listener. A Modify event is sent by the widget when the widget text
 * has changed.
 *
 * @param modifyListener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addModifyListener(ModifyListener modifyListener) {
    checkWidget();
    if (modifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(SWT.Modify, new TypedListener(modifyListener));
}
/**
 * Adds a paint object listener. A paint object event is sent by the widget when an object
 * needs to be drawn.
 *
 * @param listener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 *
 * @since 3.2
 *
 * @see PaintObjectListener
 * @see PaintObjectEvent
 */
public void addPaintObjectListener(PaintObjectListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(PaintObject, new StyledTextListener(listener));
}
/**
 * Adds a selection listener. A Selection event is sent by the widget when the
 * user changes the selection.
 * <p>
 * When <code>widgetSelected</code> is called, the event x and y fields contain
 * the start and end caret indices of the selection.
 * <code>widgetDefaultSelected</code> is not called for StyledTexts.
 * </p>
 *
 * @param listener the listener which should be notified when the user changes the receiver's selection

 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener(SelectionListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(SWT.Selection, new TypedListener(listener));
}
/**
 * Adds a verify key listener. A VerifyKey event is sent by the widget when a key
 * is pressed. The widget ignores the key press if the listener sets the doit field
 * of the event to false.
 *
 * @param listener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addVerifyKeyListener(VerifyKeyListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(VerifyKey, new StyledTextListener(listener));
}
/**
 * Adds a verify listener. A Verify event is sent by the widget when the widget text
 * is about to change. The listener can set the event text and the doit field to
 * change the text that is set in the widget or to force the widget to ignore the
 * text change.
 *
 * @param verifyListener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addVerifyListener(VerifyListener verifyListener) {
    checkWidget();
    if (verifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(SWT.Verify, new TypedListener(verifyListener));
}
/**
 * Adds a word movement listener. A movement event is sent when the boundary
 * of a word is needed. For example, this occurs during word next and word
 * previous actions.
 *
 * @param movementListener the listener
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 *
 * @see MovementEvent
 * @see MovementListener
 * @see #removeWordMovementListener
 *
 * @since 3.3
 */
public void addWordMovementListener(MovementListener movementListener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    addListener(WordNext, new StyledTextListener(movementListener));
    addListener(WordPrevious, new StyledTextListener(movementListener));
}
/**
 * Appends a string to the text at the end of the widget.
 *
 * @param string the string to be appended
 * @see #replaceTextRange(int,int,String)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void append(String string) {
    checkWidget();
    // SWT extension: allow null for zero length string
//     if (string is null) {
//         SWT.error(SWT.ERROR_NULL_ARGUMENT);
//     }
    int lastChar = Math.max(getCharCount(), 0);
    replaceTextRange(lastChar, 0, string);
}
/**
 * Calculates the scroll bars
 */
void calculateScrollBars() {
    ScrollBar horizontalBar = getHorizontalBar();
    ScrollBar verticalBar = getVerticalBar();
    setScrollBars(true);
    if (verticalBar !is null) {
        verticalBar.setIncrement(getVerticalIncrement());
    }
    if (horizontalBar !is null) {
        horizontalBar.setIncrement(getHorizontalIncrement());
    }
}
/**
 * Calculates the top index based on the current vertical scroll offset.
 * The top index is the index of the topmost fully visible line or the
 * topmost partially visible line if no line is fully visible.
 * The top index starts at 0.
 */
void calculateTopIndex(int delta) {
    int oldTopIndex = topIndex;
    int oldTopIndexY = topIndexY;
    if (isFixedLineHeight()) {
        int verticalIncrement = getVerticalIncrement();
        if (verticalIncrement is 0) {
            return;
        }
        topIndex = Compatibility.ceil(getVerticalScrollOffset(), verticalIncrement);
        // Set top index to partially visible top line if no line is fully
        // visible but at least some of the widget client area is visible.
        // Fixes bug 15088.
        if (topIndex > 0) {
            if (clientAreaHeight > 0) {
                int bottomPixel = getVerticalScrollOffset() + clientAreaHeight;
                int fullLineTopPixel = topIndex * verticalIncrement;
                int fullLineVisibleHeight = bottomPixel - fullLineTopPixel;
                // set top index to partially visible line if no line fully fits in
                // client area or if space is available but not used (the latter should
                // never happen because we use claimBottomFreeSpace)
                if (fullLineVisibleHeight < verticalIncrement) {
                    topIndex--;
                }
            } else if (topIndex >= content.getLineCount()) {
                topIndex = content.getLineCount() - 1;
            }
        }
    } else {
        if (delta >= 0) {
            delta -= topIndexY;
            int lineIndex = topIndex;
            int lineCount = content.getLineCount();
            while (lineIndex < lineCount) {
                if (delta <= 0) break;
                delta -= renderer.getLineHeight(lineIndex++);
            }
            if (lineIndex < lineCount && -delta + renderer.getLineHeight(lineIndex) <= clientAreaHeight - topMargin - bottomMargin) {
                topIndex = lineIndex;
                topIndexY = -delta;
            } else {
                topIndex = lineIndex - 1;
                topIndexY = -renderer.getLineHeight(topIndex) - delta;
            }
        } else {
            delta -= topIndexY;
            int lineIndex = topIndex;
            while (lineIndex > 0) {
                int lineHeight = renderer.getLineHeight(lineIndex - 1);
                if (delta + lineHeight > 0) break;
                delta += lineHeight;
                lineIndex--;
            }
            if (lineIndex is 0 || -delta + renderer.getLineHeight(lineIndex) <= clientAreaHeight - topMargin - bottomMargin) {
                topIndex = lineIndex;
                topIndexY = - delta;
            } else {
                topIndex = lineIndex - 1;
                topIndexY = - renderer.getLineHeight(topIndex) - delta;
            }
        }
    }
    if (topIndex !is oldTopIndex || oldTopIndexY !is topIndexY) {
        renderer.calculateClientArea();
        setScrollBars(false);
    }
}
/**
 * Hides the scroll bars if widget is created in single line mode.
 */
static int checkStyle(int style) {
    if ((style & SWT.SINGLE) !is 0) {
        style &= ~(SWT.H_SCROLL | SWT.V_SCROLL | SWT.WRAP | SWT.MULTI);
    } else {
        style |= SWT.MULTI;
        if ((style & SWT.WRAP) !is 0) {
            style &= ~SWT.H_SCROLL;
        }
    }
    style |= SWT.NO_REDRAW_RESIZE | SWT.DOUBLE_BUFFERED | SWT.NO_BACKGROUND;
    return style;
}
/**
 * Scrolls down the text to use new space made available by a resize or by
 * deleted lines.
 */
void claimBottomFreeSpace() {
    int clientAreaHeight = this.clientAreaHeight - topMargin - bottomMargin;
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        int newVerticalOffset = Math.max(0, content.getLineCount() * lineHeight - clientAreaHeight);
        if (newVerticalOffset < getVerticalScrollOffset()) {
            scrollVertical(newVerticalOffset - getVerticalScrollOffset(), true);
        }
    } else {
        int bottomIndex = getPartialBottomIndex();
        int height = getLinePixel(bottomIndex + 1);
        if (clientAreaHeight > height) {
            scrollVertical(-getAvailableHeightAbove(clientAreaHeight - height), true);
        }
    }
}
/**
 * Scrolls text to the right to use new space made available by a resize.
 */
void claimRightFreeSpace() {
    int newHorizontalOffset = Math.max(0, renderer.getWidth() - (clientAreaWidth - leftMargin - rightMargin));
    if (newHorizontalOffset < horizontalScrollOffset) {
        // item is no longer drawn past the right border of the client area
        // align the right end of the item with the right border of the
        // client area (window is scrolled right).
        scrollHorizontal(newHorizontalOffset - horizontalScrollOffset, true);
    }
}
/**
 * Removes the widget selection.
 *
 * @param sendEvent a Selection event is sent when set to true and when the selection is actually reset.
 */
void clearSelection(bool sendEvent) {
    int selectionStart = selection.x;
    int selectionEnd = selection.y;
    resetSelection();
    // redraw old selection, if any
    if (selectionEnd - selectionStart > 0) {
        int length = content.getCharCount();
        // called internally to remove selection after text is removed
        // therefore make sure redraw range is valid.
        int redrawStart = Math.min(selectionStart, length);
        int redrawEnd = Math.min(selectionEnd, length);
        if (redrawEnd - redrawStart > 0) {
            internalRedrawRange(redrawStart, redrawEnd - redrawStart);
        }
        if (sendEvent) {
            sendSelectionEvent();
        }
    }
}
public override Point computeSize (int wHint, int hHint, bool changed) {
    checkWidget();
    int lineCount = (getStyle() & SWT.SINGLE) !is 0 ? 1 : content.getLineCount();
    int width = 0;
    int height = 0;
    if (wHint is SWT.DEFAULT || hHint is SWT.DEFAULT) {
        Display display = getDisplay();
        int maxHeight = display.getClientArea().height;
        for (int lineIndex = 0; lineIndex < lineCount; lineIndex++) {
            TextLayout layout = renderer.getTextLayout(lineIndex);
            int wrapWidth = layout.getWidth();
            if (wordWrap) layout.setWidth(wHint is 0 ? 1 : wHint);
            Rectangle rect = layout.getBounds();
            height += rect.height;
            width = Math.max(width, rect.width);
            layout.setWidth(wrapWidth);
            renderer.disposeTextLayout(layout);
            if (isFixedLineHeight() && height > maxHeight) break;
        }
        if (isFixedLineHeight()) {
            height = lineCount * renderer.getLineHeight();
        }
    }
    // Use default values if no text is defined.
    if (width is 0) width = DEFAULT_WIDTH;
    if (height is 0) height = DEFAULT_HEIGHT;
    if (wHint !is SWT.DEFAULT) width = wHint;
    if (hHint !is SWT.DEFAULT) height = hHint;
    int wTrim = leftMargin + rightMargin + getCaretWidth();
    int hTrim = topMargin + bottomMargin;
    Rectangle rect = computeTrim(0, 0, width + wTrim, height + hTrim);
    return new Point (rect.width, rect.height);
}
/**
 * Copies the selected text to the <code>DND.CLIPBOARD</code> clipboard.
 * <p>
 * The text will be put on the clipboard in plain text format and RTF format.
 * The <code>DND.CLIPBOARD</code> clipboard is used for data that is
 * transferred by keyboard accelerator (such as Ctrl+C/Ctrl+V) or
 * by menu action.
 * </p>
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void copy() {
    checkWidget();
    copy(DND.CLIPBOARD);
}
/**
 * Copies the selected text to the specified clipboard.  The text will be put in the
 * clipboard in plain text format and RTF format.
 * <p>
 * The clipboardType is  one of the clipboard constants defined in class
 * <code>DND</code>.  The <code>DND.CLIPBOARD</code>  clipboard is
 * used for data that is transferred by keyboard accelerator (such as Ctrl+C/Ctrl+V)
 * or by menu action.  The <code>DND.SELECTION_CLIPBOARD</code>
 * clipboard is used for data that is transferred by selecting text and pasting
 * with the middle mouse button.
 * </p>
 *
 * @param clipboardType indicates the type of clipboard
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 3.1
 */
public void copy(int clipboardType) {
    checkWidget();
    if (clipboardType !is DND.CLIPBOARD && clipboardType !is DND.SELECTION_CLIPBOARD) return;
    int length = selection.y - selection.x;
    if (length > 0) {
        try {
            setClipboardContent(selection.x, length, clipboardType);
        } catch (SWTError error) {
            // Copy to clipboard failed. This happens when another application
            // is accessing the clipboard while we copy. Ignore the error.
            // Fixes 1GDQAVN
            // Rethrow all other errors. Fixes bug 17578.
            if (error.code !is DND.ERROR_CANNOT_SET_CLIPBOARD) {
                throw error;
            }
        }
    }
}
/**
 * Returns the alignment of the widget.
 *
 * @return the alignment
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #getLineAlignment(int)
 *
 * @since 3.2
 */
public int getAlignment() {
    checkWidget();
    return alignment;
}
int getAvailableHeightAbove(int height) {
    int maxHeight = verticalScrollOffset;
    if (maxHeight is -1) {
        int lineIndex = topIndex - 1;
        maxHeight = -topIndexY;
        if (topIndexY > 0) {
            maxHeight += renderer.getLineHeight(lineIndex--);
        }
        while (height > maxHeight && lineIndex >= 0) {
            maxHeight += renderer.getLineHeight(lineIndex--);
        }
    }
    return Math.min(height, maxHeight);
}
int getAvailableHeightBellow(int height) {
    int partialBottomIndex = getPartialBottomIndex();
    int topY = getLinePixel(partialBottomIndex);
    int lineHeight = renderer.getLineHeight(partialBottomIndex);
    int availableHeight = 0;
    int clientAreaHeight = this.clientAreaHeight - topMargin - bottomMargin;
    if (topY + lineHeight > clientAreaHeight) {
        availableHeight = lineHeight - (clientAreaHeight - topY);
    }
    int lineIndex = partialBottomIndex + 1;
    int lineCount = content.getLineCount();
    while (height > availableHeight && lineIndex < lineCount) {
        availableHeight += renderer.getLineHeight(lineIndex++);
    }
    return Math.min(height, availableHeight);
}
/**
 * Returns a string that uses only the line delimiter specified by the
 * StyledTextContent implementation.
 * <p>
 * Returns only the first line if the widget has the SWT.SINGLE style.
 * </p>
 *
 * @param text the text that may have line delimiters that don't
 *  match the model line delimiter. Possible line delimiters
 *  are CR ('\r'), LF ('\n'), CR/LF ("\r\n")
 * @return the converted text that only uses the line delimiter
 *  specified by the model. Returns only the first line if the widget
 *  has the SWT.SINGLE style.
 */
String getModelDelimitedText(String text) {
    int length = text.length;
    if (length is 0) {
        return text;
    }
    int crIndex = 0;
    int lfIndex = 0;
    int i = 0;
    StringBuffer convertedText = new StringBuffer(length);
    String delimiter = getLineDelimiter();
    while (i < length) {
        if (crIndex !is -1) {
            crIndex = text.indexOf (SWT.CR, i);
        }
        if (lfIndex !is -1) {
            lfIndex = text.indexOf (SWT.LF, i);
        }
        if (lfIndex is -1 && crIndex is -1) {   // no more line breaks?
            break;
        } else if ((crIndex < lfIndex && crIndex !is -1) || lfIndex is -1) {
            convertedText.append(text.substring(i, crIndex));
            if (lfIndex is crIndex + 1) {       // CR/LF combination?
                i = lfIndex + 1;
            } else {
                i = crIndex + 1;
            }
        } else {                                    // LF occurs before CR!
            convertedText.append(text.substring(i, lfIndex));
            i = lfIndex + 1;
        }
        if (isSingleLine()) {
            break;
        }
        convertedText.append(delimiter);
    }
    // copy remaining text if any and if not in single line mode or no
    // text copied thus far (because there only is one line)
    if (i < length && (!isSingleLine() || convertedText.length() is 0)) {
        convertedText.append(text.substring(i));
    }
    return convertedText.toString();
}
bool checkDragDetect(Event event) {
    if (!isListening(SWT.DragDetect)) return false;
    if (IS_MOTIF) {
        if (event.button !is 2) return false;
    } else {
        if (event.button !is 1) return false;
    }
    if (selection.x is selection.y) return false;
    int offset = getOffsetAtPoint(event.x, event.y, null, true);
    if (selection.x <= offset && offset < selection.y) {
        return dragDetect(event);
    }
    return false;
}
/**
 * Creates default key bindings.
 */
void createKeyBindings() {
    int nextKey = isMirrored() ? SWT.ARROW_LEFT : SWT.ARROW_RIGHT;
    int previousKey = isMirrored() ? SWT.ARROW_RIGHT : SWT.ARROW_LEFT;

    // Navigation
    setKeyBinding(SWT.ARROW_UP, ST.LINE_UP);
    setKeyBinding(SWT.ARROW_DOWN, ST.LINE_DOWN);
    if (IS_CARBON) {
        setKeyBinding(previousKey | SWT.MOD1, ST.LINE_START);
        setKeyBinding(nextKey | SWT.MOD1, ST.LINE_END);
        setKeyBinding(SWT.HOME, ST.TEXT_START);
        setKeyBinding(SWT.END, ST.TEXT_END);
        setKeyBinding(SWT.ARROW_UP | SWT.MOD1, ST.TEXT_START);
        setKeyBinding(SWT.ARROW_DOWN | SWT.MOD1, ST.TEXT_END);
        setKeyBinding(nextKey | SWT.MOD3, ST.WORD_NEXT);
        setKeyBinding(previousKey | SWT.MOD3, ST.WORD_PREVIOUS);
    } else {
        setKeyBinding(SWT.HOME, ST.LINE_START);
        setKeyBinding(SWT.END, ST.LINE_END);
        setKeyBinding(SWT.HOME | SWT.MOD1, ST.TEXT_START);
        setKeyBinding(SWT.END | SWT.MOD1, ST.TEXT_END);
        setKeyBinding(nextKey | SWT.MOD1, ST.WORD_NEXT);
        setKeyBinding(previousKey | SWT.MOD1, ST.WORD_PREVIOUS);
    }
    setKeyBinding(SWT.PAGE_UP, ST.PAGE_UP);
    setKeyBinding(SWT.PAGE_DOWN, ST.PAGE_DOWN);
    setKeyBinding(SWT.PAGE_UP | SWT.MOD1, ST.WINDOW_START);
    setKeyBinding(SWT.PAGE_DOWN | SWT.MOD1, ST.WINDOW_END);
    setKeyBinding(nextKey, ST.COLUMN_NEXT);
    setKeyBinding(previousKey, ST.COLUMN_PREVIOUS);

    // Selection
    setKeyBinding(SWT.ARROW_UP | SWT.MOD2, ST.SELECT_LINE_UP);
    setKeyBinding(SWT.ARROW_DOWN | SWT.MOD2, ST.SELECT_LINE_DOWN);
    if (IS_CARBON) {
        setKeyBinding(previousKey | SWT.MOD1 | SWT.MOD2, ST.SELECT_LINE_START);
        setKeyBinding(nextKey | SWT.MOD1 | SWT.MOD2, ST.SELECT_LINE_END);
        setKeyBinding(SWT.HOME | SWT.MOD2, ST.SELECT_TEXT_START);
        setKeyBinding(SWT.END | SWT.MOD2, ST.SELECT_TEXT_END);
        setKeyBinding(SWT.ARROW_UP | SWT.MOD1 | SWT.MOD2, ST.SELECT_TEXT_START);
        setKeyBinding(SWT.ARROW_DOWN | SWT.MOD1 | SWT.MOD2, ST.SELECT_TEXT_END);
        setKeyBinding(nextKey | SWT.MOD2 | SWT.MOD3, ST.SELECT_WORD_NEXT);
        setKeyBinding(previousKey | SWT.MOD2 | SWT.MOD3, ST.SELECT_WORD_PREVIOUS);
    } else  {
        setKeyBinding(SWT.HOME | SWT.MOD2, ST.SELECT_LINE_START);
        setKeyBinding(SWT.END | SWT.MOD2, ST.SELECT_LINE_END);
        setKeyBinding(SWT.HOME | SWT.MOD1 | SWT.MOD2, ST.SELECT_TEXT_START);
        setKeyBinding(SWT.END | SWT.MOD1 | SWT.MOD2, ST.SELECT_TEXT_END);
        setKeyBinding(nextKey | SWT.MOD1 | SWT.MOD2, ST.SELECT_WORD_NEXT);
        setKeyBinding(previousKey | SWT.MOD1 | SWT.MOD2, ST.SELECT_WORD_PREVIOUS);
    }
    setKeyBinding(SWT.PAGE_UP | SWT.MOD2, ST.SELECT_PAGE_UP);
    setKeyBinding(SWT.PAGE_DOWN | SWT.MOD2, ST.SELECT_PAGE_DOWN);
    setKeyBinding(SWT.PAGE_UP | SWT.MOD1 | SWT.MOD2, ST.SELECT_WINDOW_START);
    setKeyBinding(SWT.PAGE_DOWN | SWT.MOD1 | SWT.MOD2, ST.SELECT_WINDOW_END);
    setKeyBinding(nextKey | SWT.MOD2, ST.SELECT_COLUMN_NEXT);
    setKeyBinding(previousKey | SWT.MOD2, ST.SELECT_COLUMN_PREVIOUS);

    // Modification
    // Cut, Copy, Paste
    setKeyBinding('X' | SWT.MOD1, ST.CUT);
    setKeyBinding('C' | SWT.MOD1, ST.COPY);
    setKeyBinding('V' | SWT.MOD1, ST.PASTE);
    if (IS_CARBON) {
        setKeyBinding(SWT.DEL | SWT.MOD2, ST.DELETE_NEXT);
        setKeyBinding(SWT.BS | SWT.MOD3, ST.DELETE_WORD_PREVIOUS);
        setKeyBinding(SWT.DEL | SWT.MOD3, ST.DELETE_WORD_NEXT);
    } else {
        // Cut, Copy, Paste Wordstar style
        setKeyBinding(SWT.DEL | SWT.MOD2, ST.CUT);
        setKeyBinding(SWT.INSERT | SWT.MOD1, ST.COPY);
        setKeyBinding(SWT.INSERT | SWT.MOD2, ST.PASTE);
    }
    setKeyBinding(SWT.BS | SWT.MOD2, ST.DELETE_PREVIOUS);
    setKeyBinding(SWT.BS, ST.DELETE_PREVIOUS);
    setKeyBinding(SWT.DEL, ST.DELETE_NEXT);
    setKeyBinding(SWT.BS | SWT.MOD1, ST.DELETE_WORD_PREVIOUS);
    setKeyBinding(SWT.DEL | SWT.MOD1, ST.DELETE_WORD_NEXT);

    // Miscellaneous
    setKeyBinding(SWT.INSERT, ST.TOGGLE_OVERWRITE);
}
/**
 * Create the bitmaps to use for the caret in bidi mode.  This
 * method only needs to be called upon widget creation and when the
 * font changes (the caret bitmap height needs to match font height).
 */
void createCaretBitmaps() {
    int caretWidth = BIDI_CARET_WIDTH;
    Display display = getDisplay();
    if (leftCaretBitmap !is null) {
        if (defaultCaret !is null && leftCaretBitmap==/*eq*/defaultCaret.getImage()) {
            defaultCaret.setImage(null);
        }
        leftCaretBitmap.dispose();
    }
    int lineHeight = renderer.getLineHeight();
    leftCaretBitmap = new Image(display, caretWidth, lineHeight);
    GC gc = new GC (leftCaretBitmap);
    gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
    gc.fillRectangle(0, 0, caretWidth, lineHeight);
    gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
    gc.drawLine(0,0,0,lineHeight);
    gc.drawLine(0,0,caretWidth-1,0);
    gc.drawLine(0,1,1,1);
    gc.dispose();

    if (rightCaretBitmap !is null) {
        if (defaultCaret !is null && rightCaretBitmap==/*eq*/defaultCaret.getImage()) {
            defaultCaret.setImage(null);
        }
        rightCaretBitmap.dispose();
    }
    rightCaretBitmap = new Image(display, caretWidth, lineHeight);
    gc = new GC (rightCaretBitmap);
    gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
    gc.fillRectangle(0, 0, caretWidth, lineHeight);
    gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
    gc.drawLine(caretWidth-1,0,caretWidth-1,lineHeight);
    gc.drawLine(0,0,caretWidth-1,0);
    gc.drawLine(caretWidth-1,1,1,1);
    gc.dispose();
}
/**
 * Moves the selected text to the clipboard.  The text will be put in the
 * clipboard in plain text format and RTF format.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void cut(){
    checkWidget();
    int length = selection.y - selection.x;
    if (length > 0) {
        try {
            setClipboardContent(selection.x, length, DND.CLIPBOARD);
        } catch (SWTError error) {
            // Copy to clipboard failed. This happens when another application
            // is accessing the clipboard while we copy. Ignore the error.
            // Fixes 1GDQAVN
            // Rethrow all other errors. Fixes bug 17578.
            if (error.code !is DND.ERROR_CANNOT_SET_CLIPBOARD) {
                throw error;
            }
            // Abort cut operation if copy to clipboard fails.
            // Fixes bug 21030.
            return;
        }
        doDelete();
    }
}
/**
 * A mouse move event has occurred.  See if we should start autoscrolling.  If
 * the move position is outside of the client area, initiate autoscrolling.
 * Otherwise, we've moved back into the widget so end autoscrolling.
 */
void doAutoScroll(Event event) {
    if (event.y > clientAreaHeight) {
        doAutoScroll(SWT.DOWN, event.y - clientAreaHeight);
    } else if (event.y < 0) {
        doAutoScroll(SWT.UP, -event.y);
    } else if (event.x < leftMargin && !wordWrap) {
        doAutoScroll(ST.COLUMN_PREVIOUS, leftMargin - event.x);
    } else if (event.x > clientAreaWidth - leftMargin - rightMargin && !wordWrap) {
        doAutoScroll(ST.COLUMN_NEXT, event.x - (clientAreaWidth - leftMargin - rightMargin));
    } else {
        endAutoScroll();
    }
}
/**
 * Initiates autoscrolling.
 *
 * @param direction SWT.UP, SWT.DOWN, SWT.COLUMN_NEXT, SWT.COLUMN_PREVIOUS
 */
void doAutoScroll(int direction, int distance) {
    autoScrollDistance = distance;
    // If we're already autoscrolling in the given direction do nothing
    if (autoScrollDirection is direction) {
        return;
    }

    Runnable timer = null;
    Display disp = getDisplay();
    // Set a timer that will simulate the user pressing and holding
    // down a cursor key (i.e., arrowUp, arrowDown).
    if (direction is SWT.UP) {
        timer = new class(disp) Runnable {
            Display display;
            this( Display d ){ this.display = d; }
            public void run() {
                if (autoScrollDirection is SWT.UP) {
                    doSelectionPageUp(autoScrollDistance);
                    display.timerExec(V_SCROLL_RATE, this);
                }
            }
        };
        autoScrollDirection = direction;
        display.timerExec(V_SCROLL_RATE, timer);
    } else if (direction is SWT.DOWN) {
        timer = new class(disp) Runnable {
            Display display;
            this( Display d ){ this.display = d; }
            public void run() {
                if (autoScrollDirection is SWT.DOWN) {
                    doSelectionPageDown(autoScrollDistance);
                    display.timerExec(V_SCROLL_RATE, this);
                }
            }
        };
        autoScrollDirection = direction;
        display.timerExec(V_SCROLL_RATE, timer);
    } else if (direction is ST.COLUMN_NEXT) {
        timer = new class(disp) Runnable {
            Display display;
            this( Display d ){ this.display = d; }
            public void run() {
                if (autoScrollDirection is ST.COLUMN_NEXT) {
                    doVisualNext();
                    setMouseWordSelectionAnchor();
                    doMouseSelection();
                    display.timerExec(H_SCROLL_RATE, this);
                }
            }
        };
        autoScrollDirection = direction;
        display.timerExec(H_SCROLL_RATE, timer);
    } else if (direction is ST.COLUMN_PREVIOUS) {
        timer = new class(disp) Runnable {
            Display display;
            this( Display d ){ this.display = d; }
            public void run() {
                if (autoScrollDirection is ST.COLUMN_PREVIOUS) {
                    doVisualPrevious();
                    setMouseWordSelectionAnchor();
                    doMouseSelection();
                    display.timerExec(H_SCROLL_RATE, this);
                }
            }
        };
        autoScrollDirection = direction;
        display.timerExec(H_SCROLL_RATE, timer);
    }
}
/**
 * Deletes the previous character. Delete the selected text if any.
 * Move the caret in front of the deleted text.
 */
void doBackspace() {
    Event event = new Event();
    event.text = "";
    if (selection.x !is selection.y) {
        event.start = selection.x;
        event.end = selection.y;
        sendKeyEvent(event);
    } else if (caretOffset > 0) {
        int lineIndex = content.getLineAtOffset(caretOffset);
        int lineOffset = content.getOffsetAtLine(lineIndex);
        if (caretOffset is lineOffset) {
            // SWT: on line start, delete line break
            lineOffset = content.getOffsetAtLine(lineIndex - 1);
            event.start = lineOffset + content.getLine(lineIndex - 1).length;
            event.end = caretOffset;
        } else {
            TextLayout layout = renderer.getTextLayout(lineIndex);
            int start = layout.getPreviousOffset(caretOffset - lineOffset, SWT.MOVEMENT_CLUSTER);
            renderer.disposeTextLayout(layout);
            event.start = start + lineOffset;
            event.end = caretOffset;
        }
        sendKeyEvent(event);
    }
}
/**
 * Replaces the selection with the character or insert the character at the
 * current caret position if no selection exists.
 * <p>
 * If a carriage return was typed replace it with the line break character
 * used by the widget on this platform.
 * </p>
 *
 * @param key the character typed by the user
 */
void doContent(dchar key) {
    Event event = new Event();
    event.start = selection.x;
    event.end = selection.y;
    // replace a CR line break with the widget line break
    // CR does not make sense on Windows since most (all?) applications
    // don't recognize CR as a line break.
    if (key is SWT.CR || key is SWT.LF) {
        if (!isSingleLine()) {
            event.text = getLineDelimiter();
        }
    } else if (selection.x is selection.y && overwrite && key !is TAB) {
        // no selection and overwrite mode is on and the typed key is not a
        // tab character (tabs are always inserted without overwriting)?
        int lineIndex = content.getLineAtOffset(event.end);
        int lineOffset = content.getOffsetAtLine(lineIndex);
        String line = content.getLine(lineIndex);
        // replace character at caret offset if the caret is not at the
        // end of the line
        if (event.end < lineOffset + line.length) {
            event.end+=dcharToString( key ).length;
        }
        event.text = dcharToString( key );
    } else {
        event.text = dcharToString( key );
    }
    if (event.text !is null) {
        if (textLimit > 0 && content.getCharCount() - (event.end - event.start) >= textLimit) {
            return;
        }
        sendKeyEvent(event);
    }
}
/**
 * Moves the caret after the last character of the widget content.
 */
void doContentEnd() {
    // place caret at end of first line if receiver is in single
    // line mode. fixes 4820.
    if (isSingleLine()) {
        doLineEnd();
    } else {
        int length = content.getCharCount();
        if (caretOffset < length) {
            caretOffset = length;
            showCaret();
        }
    }
}
/**
 * Moves the caret in front of the first character of the widget content.
 */
void doContentStart() {
    if (caretOffset > 0) {
        caretOffset = 0;
        showCaret();
    }
}
/**
 * Moves the caret to the start of the selection if a selection exists.
 * Otherwise, if no selection exists move the cursor according to the
 * cursor selection rules.
 *
 * @see #doSelectionCursorPrevious
 */
void doCursorPrevious() {
    if (selection.y - selection.x > 0) {
        caretOffset = selection.x;
        caretAlignment = OFFSET_LEADING;
        showCaret();
    } else {
        doSelectionCursorPrevious();
    }
}
/**
 * Moves the caret to the end of the selection if a selection exists.
 * Otherwise, if no selection exists move the cursor according to the
 * cursor selection rules.
 *
 * @see #doSelectionCursorNext
 */
void doCursorNext() {
    if (selection.y - selection.x > 0) {
        caretOffset = selection.y;
        caretAlignment = PREVIOUS_OFFSET_TRAILING;
        showCaret();
    } else {
        doSelectionCursorNext();
    }
}
/**
 * Deletes the next character. Delete the selected text if any.
 */
void doDelete() {
    Event event = new Event();
    event.text = "";
    if (selection.x !is selection.y) {
        event.start = selection.x;
        event.end = selection.y;
        sendKeyEvent(event);
    } else if (caretOffset < content.getCharCount()) {
        int line = content.getLineAtOffset(caretOffset);
        int lineOffset = content.getOffsetAtLine(line);
        int lineLength = content.getLine(line).length;
        if (caretOffset is lineOffset + lineLength) {
            event.start = caretOffset;
            event.end = content.getOffsetAtLine(line + 1);
        } else {
            event.start = caretOffset;
            event.end = getClusterNext(caretOffset, line);
        }
        sendKeyEvent(event);
    }
}
/**
 * Deletes the next word.
 */
void doDeleteWordNext() {
    if (selection.x !is selection.y) {
        // if a selection exists, treat the as if
        // only the delete key was pressed
        doDelete();
    } else {
        Event event = new Event();
        event.text = "";
        event.start = caretOffset;
        event.end = getWordNext(caretOffset, SWT.MOVEMENT_WORD);
        sendKeyEvent(event);
    }
}
/**
 * Deletes the previous word.
 */
void doDeleteWordPrevious() {
    if (selection.x !is selection.y) {
        // if a selection exists, treat as if
        // only the backspace key was pressed
        doBackspace();
    } else {
        Event event = new Event();
        event.text = "";
        event.start = getWordPrevious(caretOffset, SWT.MOVEMENT_WORD);
        event.end = caretOffset;
        sendKeyEvent(event);
    }
}
/**
 * Moves the caret one line down and to the same character offset relative
 * to the beginning of the line. Move the caret to the end of the new line
 * if the new line is shorter than the character offset.
 */
void doLineDown(bool select) {
    int caretLine = getCaretLine();
    int lineCount = content.getLineCount();
    int y = 0;
    bool lastLine = false;
    if (wordWrap) {
        int lineOffset = content.getOffsetAtLine(caretLine);
        int offsetInLine = caretOffset - lineOffset;
        TextLayout layout = renderer.getTextLayout(caretLine);
        int lineIndex = getVisualLineIndex(layout, offsetInLine);
        int layoutLineCount = layout.getLineCount();
        if (lineIndex is layoutLineCount - 1) {
            lastLine = caretLine is lineCount - 1;
            caretLine++;
        } else {
            y = layout.getLineBounds(lineIndex + 1).y;
        }
        renderer.disposeTextLayout(layout);
    } else {
        lastLine = caretLine is lineCount - 1;
        caretLine++;
    }
    if (lastLine) {
        if (select) caretOffset = content.getCharCount();
    } else {
        caretOffset = getOffsetAtPoint(columnX, y, caretLine);
    }
    int oldColumnX = columnX;
    int oldHScrollOffset = horizontalScrollOffset;
    if (select) {
        setMouseWordSelectionAnchor();
        // select first and then scroll to reduce flash when key
        // repeat scrolls lots of lines
        doSelection(ST.COLUMN_NEXT);
    }
    showCaret();
    int hScrollChange = oldHScrollOffset - horizontalScrollOffset;
    columnX = oldColumnX + hScrollChange;
}
/**
 * Moves the caret to the end of the line.
 */
void doLineEnd() {
    int caretLine = getCaretLine();
    int lineOffset = content.getOffsetAtLine(caretLine);
    int lineEndOffset;
    if (wordWrap) {
        TextLayout layout = renderer.getTextLayout(caretLine);
        int offsetInLine = caretOffset - lineOffset;
        int lineIndex = getVisualLineIndex(layout, offsetInLine);
        int[] offsets = layout.getLineOffsets();
        lineEndOffset = lineOffset + offsets[lineIndex + 1];
        renderer.disposeTextLayout(layout);
    } else {
        int lineLength = content.getLine(caretLine).length;
        lineEndOffset = lineOffset + lineLength;
    }
    if (caretOffset < lineEndOffset) {
        caretOffset = lineEndOffset;
        caretAlignment = PREVIOUS_OFFSET_TRAILING;
        showCaret();
    }
}
/**
 * Moves the caret to the beginning of the line.
 */
void doLineStart() {
    int caretLine = getCaretLine();
    int lineOffset = content.getOffsetAtLine(caretLine);
    if (wordWrap) {
        TextLayout layout = renderer.getTextLayout(caretLine);
        int offsetInLine = caretOffset - lineOffset;
        int lineIndex = getVisualLineIndex(layout, offsetInLine);
        int[] offsets = layout.getLineOffsets();
        lineOffset += offsets[lineIndex];
        renderer.disposeTextLayout(layout);
    }
    if (caretOffset > lineOffset) {
        caretOffset = lineOffset;
        caretAlignment = OFFSET_LEADING;
        showCaret();
    }
}
/**
 * Moves the caret one line up and to the same character offset relative
 * to the beginning of the line. Move the caret to the end of the new line
 * if the new line is shorter than the character offset.
 */
void doLineUp(bool select) {
    int caretLine = getCaretLine(), y = 0;
    bool firstLine = false;
    if (wordWrap) {
        int lineOffset = content.getOffsetAtLine(caretLine);
        int offsetInLine = caretOffset - lineOffset;
        TextLayout layout = renderer.getTextLayout(caretLine);
        int lineIndex = getVisualLineIndex(layout, offsetInLine);
        if (lineIndex is 0) {
            firstLine = caretLine is 0;
            if (!firstLine) {
                caretLine--;
                y = renderer.getLineHeight(caretLine) - 1;
            }
        } else {
            y = layout.getLineBounds(lineIndex - 1).y;
        }
        renderer.disposeTextLayout(layout);
    } else {
        firstLine = caretLine is 0;
        caretLine--;
    }
    if (firstLine) {
        if (select) caretOffset = 0;
    } else {
        caretOffset = getOffsetAtPoint(columnX, y, caretLine);
    }
    int oldColumnX = columnX;
    int oldHScrollOffset = horizontalScrollOffset;
    if (select) setMouseWordSelectionAnchor();
    showCaret();
    if (select) doSelection(ST.COLUMN_PREVIOUS);
    int hScrollChange = oldHScrollOffset - horizontalScrollOffset;
    columnX = oldColumnX + hScrollChange;
}
/**
 * Moves the caret to the specified location.
 *
 * @param x x location of the new caret position
 * @param y y location of the new caret position
 * @param select the location change is a selection operation.
 *  include the line delimiter in the selection
 */
void doMouseLocationChange(int x, int y, bool select) {
    int line = getLineIndex(y);

    updateCaretDirection = true;
    // allow caret to be placed below first line only if receiver is
    // not in single line mode. fixes 4820.
    if (line < 0 || (isSingleLine() && line > 0)) {
        return;
    }
    int oldCaretAlignment = caretAlignment;
    int newCaretOffset = getOffsetAtPoint(x, y);

    if (doubleClickEnabled && clickCount > 1) {
        newCaretOffset = doMouseWordSelect(x, newCaretOffset, line);
    }

    int newCaretLine = content.getLineAtOffset(newCaretOffset);

    // Is the mouse within the left client area border or on
    // a different line? If not the autoscroll selection
    // could be incorrectly reset. Fixes 1GKM3XS
    if (0 <= y && y < clientAreaHeight &&
        (0 <= x && x < clientAreaWidth || wordWrap ||
        newCaretLine !is content.getLineAtOffset(caretOffset))) {
        if (newCaretOffset !is caretOffset || caretAlignment !is oldCaretAlignment) {
            caretOffset = newCaretOffset;
            if (select) doMouseSelection();
            showCaret();
        }
    }
    if (!select) {
        caretOffset = newCaretOffset;
        clearSelection(true);
    }
}
/**
 * Updates the selection based on the caret position
 */
void doMouseSelection() {
    if (caretOffset <= selection.x ||
        (caretOffset > selection.x &&
         caretOffset < selection.y && selectionAnchor is selection.x)) {
        doSelection(ST.COLUMN_PREVIOUS);
    } else {
        doSelection(ST.COLUMN_NEXT);
    }
}
/**
 * Returns the offset of the word at the specified offset.
 * If the current selection extends from high index to low index
 * (i.e., right to left, or caret is at left border of selection on
 * non-bidi platforms) the start offset of the word preceding the
 * selection is returned. If the current selection extends from
 * low index to high index the end offset of the word following
 * the selection is returned.
 *
 * @param x mouse x location
 * @param newCaretOffset caret offset of the mouse cursor location
 * @param line line index of the mouse cursor location
 */
int doMouseWordSelect(int x, int newCaretOffset, int line) {
    // flip selection anchor based on word selection direction from
    // base double click. Always do this here (and don't rely on doAutoScroll)
    // because auto scroll only does not cover all possible mouse selections
    // (e.g., mouse x < 0 && mouse y > caret line y)
    if (newCaretOffset < selectionAnchor && selectionAnchor is selection.x) {
        selectionAnchor = doubleClickSelection.y;
    } else if (newCaretOffset > selectionAnchor && selectionAnchor is selection.y) {
        selectionAnchor = doubleClickSelection.x;
    }
    if (0 <= x && x < clientAreaWidth) {
        bool wordSelect = (clickCount & 1) is 0;
        if (caretOffset is selection.x) {
            if (wordSelect) {
                newCaretOffset = getWordPrevious(newCaretOffset, SWT.MOVEMENT_WORD_START);
            } else {
                newCaretOffset = content.getOffsetAtLine(line);
            }
        } else {
            if (wordSelect) {
                newCaretOffset = getWordNext(newCaretOffset, SWT.MOVEMENT_WORD_END);
            } else {
                int lineEnd = content.getCharCount();
                if (line + 1 < content.getLineCount()) {
                    lineEnd = content.getOffsetAtLine(line + 1);
                }
                newCaretOffset = lineEnd;
            }
        }
    }
    return newCaretOffset;
}
/**
 * Scrolls one page down so that the last line (truncated or whole)
 * of the current page becomes the fully visible top line.
 * <p>
 * The caret is scrolled the same number of lines so that its location
 * relative to the top line remains the same. The exception is the end
 * of the text where a full page scroll is not possible. In this case
 * the caret is moved after the last character.
 * </p>
 *
 * @param select whether or not to select the page
 */
void doPageDown(bool select, int height) {
    if (isSingleLine()) return;
    int oldColumnX = columnX;
    int oldHScrollOffset = horizontalScrollOffset;
    if (isFixedLineHeight()) {
        int lineCount = content.getLineCount();
        int caretLine = getCaretLine();
        if (caretLine < lineCount - 1) {
            int lineHeight = renderer.getLineHeight();
            int lines = (height is -1 ? clientAreaHeight : height) / lineHeight;
            int scrollLines = Math.min(lineCount - caretLine - 1, lines);
            // ensure that scrollLines never gets negative and at least one
            // line is scrolled. fixes bug 5602.
            scrollLines = Math.max(1, scrollLines);
            caretOffset = getOffsetAtPoint(columnX, getLinePixel(caretLine + scrollLines));
            if (select) {
                doSelection(ST.COLUMN_NEXT);
            }
            // scroll one page down or to the bottom
            int verticalMaximum = lineCount * getVerticalIncrement();
            int pageSize = clientAreaHeight;
            int verticalScrollOffset = getVerticalScrollOffset();
            int scrollOffset = verticalScrollOffset + scrollLines * getVerticalIncrement();
            if (scrollOffset + pageSize > verticalMaximum) {
                scrollOffset = verticalMaximum - pageSize;
            }
            if (scrollOffset > verticalScrollOffset) {
                scrollVertical(scrollOffset - verticalScrollOffset, true);
            }
        }
    } else {
        int lineCount = content.getLineCount();
        int caretLine = getCaretLine();
        int lineIndex, lineHeight;
        if (height is -1) {
            lineIndex = getPartialBottomIndex();
            int topY = getLinePixel(lineIndex);
            lineHeight = renderer.getLineHeight(lineIndex);
            height = topY;
            if (topY + lineHeight <= clientAreaHeight) {
                height += lineHeight;
            } else {
                if (wordWrap) {
                    TextLayout layout = renderer.getTextLayout(lineIndex);
                    int y = clientAreaHeight - topY;
                    for (int i = 0; i < layout.getLineCount(); i++) {
                        Rectangle bounds = layout.getLineBounds(i);
                        if (bounds.contains(bounds.x, y)) {
                            height += bounds.y;
                            break;
                        }
                    }
                    renderer.disposeTextLayout(layout);
                }
            }
        } else {
            lineIndex = getLineIndex(height);
            int topLineY = getLinePixel(lineIndex);
            if (wordWrap) {
                TextLayout layout = renderer.getTextLayout(lineIndex);
                int y = height - topLineY;
                for (int i = 0; i < layout.getLineCount(); i++) {
                    Rectangle bounds = layout.getLineBounds(i);
                    if (bounds.contains(bounds.x, y)) {
                        height = topLineY + bounds.y + bounds.height;
                        break;
                    }
                }
                renderer.disposeTextLayout(layout);
            } else {
                height = topLineY + renderer.getLineHeight(lineIndex);
            }
        }
        int caretHeight = height;
        if (wordWrap) {
            TextLayout layout = renderer.getTextLayout(caretLine);
            int offsetInLine = caretOffset - content.getOffsetAtLine(caretLine);
            lineIndex = getVisualLineIndex(layout, offsetInLine);
            caretHeight += layout.getLineBounds(lineIndex).y;
            renderer.disposeTextLayout(layout);
        }
        lineIndex = caretLine;
        lineHeight = renderer.getLineHeight(lineIndex);
        while (caretHeight - lineHeight >= 0 && lineIndex < lineCount - 1) {
            caretHeight -= lineHeight;
            lineHeight = renderer.getLineHeight(++lineIndex);
        }
        caretOffset = getOffsetAtPoint(columnX, caretHeight, lineIndex);
        if (select) doSelection(ST.COLUMN_NEXT);
        height = getAvailableHeightBellow(height);
        scrollVertical(height, true);
        if (height is 0) setCaretLocation();
    }
    showCaret();
    int hScrollChange = oldHScrollOffset - horizontalScrollOffset;
    columnX = oldColumnX + hScrollChange;
}
/**
 * Moves the cursor to the end of the last fully visible line.
 */
void doPageEnd() {
    // go to end of line if in single line mode. fixes 5673
    if (isSingleLine()) {
        doLineEnd();
    } else {
        int bottomOffset;
        if (wordWrap) {
            int lineIndex = getPartialBottomIndex();
            TextLayout layout = renderer.getTextLayout(lineIndex);
            int y = (clientAreaHeight - bottomMargin) - getLinePixel(lineIndex);
            int index = layout.getLineCount() - 1;
            while (index >= 0) {
                Rectangle bounds = layout.getLineBounds(index);
                if (y >= bounds.y + bounds.height) break;
                index--;
            }
            if (index is -1 && lineIndex > 0) {
                bottomOffset = content.getOffsetAtLine(lineIndex - 1) + content.getLine(lineIndex - 1).length;
            } else {
                bottomOffset = content.getOffsetAtLine(lineIndex) + Math.max(0, layout.getLineOffsets()[index + 1] - 1);
            }
            renderer.disposeTextLayout(layout);
        } else {
            int lineIndex = getBottomIndex();
            bottomOffset = content.getOffsetAtLine(lineIndex) + content.getLine(lineIndex).length;
        }
        if (caretOffset < bottomOffset) {
            caretOffset = bottomOffset;
            caretAlignment = OFFSET_LEADING;
            showCaret();
        }
    }
}
/**
 * Moves the cursor to the beginning of the first fully visible line.
 */
void doPageStart() {
    int topOffset;
    if (wordWrap) {
        int y, lineIndex;
        if (topIndexY > 0) {
            lineIndex = topIndex - 1;
            y = renderer.getLineHeight(lineIndex) - topIndexY;
        } else {
            lineIndex = topIndex;
            y = -topIndexY;
        }
        TextLayout layout = renderer.getTextLayout(lineIndex);
        int index = 0;
        int lineCount = layout.getLineCount();
        while (index < lineCount) {
            Rectangle bounds = layout.getLineBounds(index);
            if (y <= bounds.y) break;
            index++;
        }
        if (index is lineCount) {
            topOffset = content.getOffsetAtLine(lineIndex + 1);
        } else {
            topOffset = content.getOffsetAtLine(lineIndex) + layout.getLineOffsets()[index];
        }
        renderer.disposeTextLayout(layout);
    } else {
        topOffset = content.getOffsetAtLine(topIndex);
    }
    if (caretOffset > topOffset) {
        caretOffset = topOffset;
        caretAlignment = OFFSET_LEADING;
        showCaret();
    }
}
/**
 * Scrolls one page up so that the first line (truncated or whole)
 * of the current page becomes the fully visible last line.
 * The caret is scrolled the same number of lines so that its location
 * relative to the top line remains the same. The exception is the beginning
 * of the text where a full page scroll is not possible. In this case the
 * caret is moved in front of the first character.
 */
void doPageUp(bool select, int height) {
    if (isSingleLine()) return;
    int oldHScrollOffset = horizontalScrollOffset;
    int oldColumnX = columnX;
    if (isFixedLineHeight()) {
        int caretLine = getCaretLine();
        if (caretLine > 0) {
            int lineHeight = renderer.getLineHeight();
            int lines = (height is -1 ? clientAreaHeight : height) / lineHeight;
            int scrollLines = Math.max(1, Math.min(caretLine, lines));
            caretLine -= scrollLines;
            caretOffset = getOffsetAtPoint(columnX, getLinePixel(caretLine));
            if (select) {
                doSelection(ST.COLUMN_PREVIOUS);
            }
            int verticalScrollOffset = getVerticalScrollOffset();
            int scrollOffset = Math.max(0, verticalScrollOffset - scrollLines * getVerticalIncrement());
            if (scrollOffset < verticalScrollOffset) {
                scrollVertical(scrollOffset - verticalScrollOffset, true);
            }
        }
    } else {
        int caretLine = getCaretLine();
        int lineHeight, lineIndex;
        if (height is -1) {
            if (topIndexY is 0) {
                height = clientAreaHeight;
            } else {
                int y;
                if (topIndex > 0) {
                    lineIndex = topIndex - 1;
                    lineHeight = renderer.getLineHeight(lineIndex);
                    height = clientAreaHeight - topIndexY;
                    y = lineHeight - topIndexY;
                } else {
                    lineIndex = topIndex;
                    lineHeight = renderer.getLineHeight(lineIndex);
                    height = clientAreaHeight - (lineHeight + topIndexY);
                    y = -topIndexY;
                }
                if (wordWrap) {
                    TextLayout layout = renderer.getTextLayout(lineIndex);
                    for (int i = 0; i < layout.getLineCount(); i++) {
                        Rectangle bounds = layout.getLineBounds(i);
                        if (bounds.contains(bounds.x, y)) {
                            height += lineHeight - (bounds.y + bounds.height);
                            break;
                        }
                    }
                    renderer.disposeTextLayout(layout);
                }
            }
        } else {
            lineIndex = getLineIndex(clientAreaHeight - height);
            int topLineY = getLinePixel(lineIndex);
            if (wordWrap) {
                TextLayout layout = renderer.getTextLayout(lineIndex);
                int y = topLineY;
                for (int i = 0; i < layout.getLineCount(); i++) {
                    Rectangle bounds = layout.getLineBounds(i);
                    if (bounds.contains(bounds.x, y)) {
                        height = clientAreaHeight - (topLineY + bounds.y);
                        break;
                    }
                }
                renderer.disposeTextLayout(layout);
            } else {
                height = clientAreaHeight - topLineY;
            }
        }
        int caretHeight = height;
        if (wordWrap) {
            TextLayout layout = renderer.getTextLayout(caretLine);
            int offsetInLine = caretOffset - content.getOffsetAtLine(caretLine);
            lineIndex = getVisualLineIndex(layout, offsetInLine);
            caretHeight += layout.getBounds().height - layout.getLineBounds(lineIndex).y;
            renderer.disposeTextLayout(layout);
        }
        lineIndex = caretLine;
        lineHeight = renderer.getLineHeight(lineIndex);
        while (caretHeight - lineHeight >= 0 && lineIndex > 0) {
            caretHeight -= lineHeight;
            lineHeight = renderer.getLineHeight(--lineIndex);
        }
        lineHeight = renderer.getLineHeight(lineIndex);
        caretOffset = getOffsetAtPoint(columnX, lineHeight - caretHeight, lineIndex);
        if (select) doSelection(ST.COLUMN_PREVIOUS);
        height = getAvailableHeightAbove(height);
        scrollVertical(-height, true);
        if (height is 0) setCaretLocation();
    }
    showCaret();
    int hScrollChange = oldHScrollOffset - horizontalScrollOffset;
    columnX = oldColumnX + hScrollChange;
}
/**
 * Updates the selection to extend to the current caret position.
 */
void doSelection(int direction) {
    int redrawStart = -1;
    int redrawEnd = -1;
    if (selectionAnchor is -1) {
        selectionAnchor = selection.x;
    }
    if (direction is ST.COLUMN_PREVIOUS) {
        if (caretOffset < selection.x) {
            // grow selection
            redrawEnd = selection.x;
            redrawStart = selection.x = caretOffset;
            // check if selection has reversed direction
            if (selection.y !is selectionAnchor) {
                redrawEnd = selection.y;
                selection.y = selectionAnchor;
            }
        // test whether selection actually changed. Fixes 1G71EO1
        } else if (selectionAnchor is selection.x && caretOffset < selection.y) {
            // caret moved towards selection anchor (left side of selection).
            // shrink selection
            redrawEnd = selection.y;
            redrawStart = selection.y = caretOffset;
        }
    } else {
        if (caretOffset > selection.y) {
            // grow selection
            redrawStart = selection.y;
            redrawEnd = selection.y = caretOffset;
            // check if selection has reversed direction
            if (selection.x !is selectionAnchor) {
                redrawStart = selection.x;
                selection.x = selectionAnchor;
            }
        // test whether selection actually changed. Fixes 1G71EO1
        } else if (selectionAnchor is selection.y && caretOffset > selection.x) {
            // caret moved towards selection anchor (right side of selection).
            // shrink selection
            redrawStart = selection.x;
            redrawEnd = selection.x = caretOffset;
        }
    }
    if (redrawStart !is -1 && redrawEnd !is -1) {
        internalRedrawRange(redrawStart, redrawEnd - redrawStart);
        sendSelectionEvent();
    }
}
/**
 * Moves the caret to the next character or to the beginning of the
 * next line if the cursor is at the end of a line.
 */
void doSelectionCursorNext() {
    int caretLine = getCaretLine();
    int lineOffset = content.getOffsetAtLine(caretLine);
    int offsetInLine = caretOffset - lineOffset;
    if (offsetInLine < content.getLine(caretLine).length) {
        TextLayout layout = renderer.getTextLayout(caretLine);
        offsetInLine = layout.getNextOffset(offsetInLine, SWT.MOVEMENT_CLUSTER);
        int lineStart = layout.getLineOffsets()[layout.getLineIndex(offsetInLine)];
        renderer.disposeTextLayout(layout);
        caretOffset = offsetInLine + lineOffset;
        caretAlignment = offsetInLine is lineStart ? OFFSET_LEADING : PREVIOUS_OFFSET_TRAILING;
        showCaret();
    } else if (caretLine < content.getLineCount() - 1 && !isSingleLine()) {
        caretLine++;
        caretOffset = content.getOffsetAtLine(caretLine);
        caretAlignment = PREVIOUS_OFFSET_TRAILING;
        showCaret();
    }
}
/**
 * Moves the caret to the previous character or to the end of the previous
 * line if the cursor is at the beginning of a line.
 */
void doSelectionCursorPrevious() {
    int caretLine = getCaretLine();
    int lineOffset = content.getOffsetAtLine(caretLine);
    int offsetInLine = caretOffset - lineOffset;
    caretAlignment = OFFSET_LEADING;

    if (offsetInLine > 0) {
        caretOffset = getClusterPrevious(caretOffset, caretLine);
        showCaret();
    } else if (caretLine > 0) {
        caretLine--;
        lineOffset = content.getOffsetAtLine(caretLine);
        caretOffset = lineOffset + content.getLine(caretLine).length;
        showCaret();
    }
}
/**
 * Moves the caret one line down and to the same character offset relative
 * to the beginning of the line. Moves the caret to the end of the new line
 * if the new line is shorter than the character offset.
 * Moves the caret to the end of the text if the caret already is on the
 * last line.
 * Adjusts the selection according to the caret change. This can either add
 * to or subtract from the old selection, depending on the previous selection
 * direction.
 */
void doSelectionLineDown() {
    int oldColumnX = columnX = getPointAtOffset(caretOffset).x;
    doLineDown(true);
    columnX = oldColumnX;
}
/**
 * Moves the caret one line up and to the same character offset relative
 * to the beginning of the line. Moves the caret to the end of the new line
 * if the new line is shorter than the character offset.
 * Moves the caret to the beginning of the document if it is already on the
 * first line.
 * Adjusts the selection according to the caret change. This can either add
 * to or subtract from the old selection, depending on the previous selection
 * direction.
 */
void doSelectionLineUp() {
    int oldColumnX = columnX = getPointAtOffset(caretOffset).x;
    doLineUp(true);
    columnX = oldColumnX;
}
/**
 * Scrolls one page down so that the last line (truncated or whole)
 * of the current page becomes the fully visible top line.
 * <p>
 * The caret is scrolled the same number of lines so that its location
 * relative to the top line remains the same. The exception is the end
 * of the text where a full page scroll is not possible. In this case
 * the caret is moved after the last character.
 * <p></p>
 * Adjusts the selection according to the caret change. This can either add
 * to or subtract from the old selection, depending on the previous selection
 * direction.
 * </p>
 */
void doSelectionPageDown(int pixels) {
    int oldColumnX = columnX = getPointAtOffset(caretOffset).x;
    doPageDown(true, pixels);
    columnX = oldColumnX;
}
/**
 * Scrolls one page up so that the first line (truncated or whole)
 * of the current page becomes the fully visible last line.
 * <p>
 * The caret is scrolled the same number of lines so that its location
 * relative to the top line remains the same. The exception is the beginning
 * of the text where a full page scroll is not possible. In this case the
 * caret is moved in front of the first character.
 * </p><p>
 * Adjusts the selection according to the caret change. This can either add
 * to or subtract from the old selection, depending on the previous selection
 * direction.
 * </p>
 */
void doSelectionPageUp(int pixels) {
    int oldColumnX = columnX = getPointAtOffset(caretOffset).x;
    doPageUp(true, pixels);
    columnX = oldColumnX;
}
/**
 * Moves the caret to the end of the next word .
 */
void doSelectionWordNext() {
    int newCaretOffset = getWordNext(caretOffset, SWT.MOVEMENT_WORD);
    // Force symmetrical movement for word next and previous. Fixes 14536
    caretAlignment = OFFSET_LEADING;
    // don't change caret position if in single line mode and the cursor
    // would be on a different line. fixes 5673
    if (!isSingleLine() ||
        content.getLineAtOffset(caretOffset) is content.getLineAtOffset(newCaretOffset)) {
        caretOffset = newCaretOffset;
        showCaret();
    }
}
/**
 * Moves the caret to the start of the previous word.
 */
void doSelectionWordPrevious() {
    caretAlignment = OFFSET_LEADING;
    caretOffset = getWordPrevious(caretOffset, SWT.MOVEMENT_WORD);
    int caretLine = content.getLineAtOffset(caretOffset);
    // word previous always comes from bottom line. when
    // wrapping lines, stay on bottom line when on line boundary
    if (wordWrap && caretLine < content.getLineCount() - 1 &&
        caretOffset is content.getOffsetAtLine(caretLine + 1)) {
        caretLine++;
    }
    showCaret();
}
/**
 * Moves the caret one character to the left.  Do not go to the previous line.
 * When in a bidi locale and at a R2L character the caret is moved to the
 * beginning of the R2L segment (visually right) and then one character to the
 * left (visually left because it's now in a L2R segment).
 */
void doVisualPrevious() {
    caretOffset = getClusterPrevious(caretOffset, getCaretLine());
    showCaret();
}
/**
 * Moves the caret one character to the right.  Do not go to the next line.
 * When in a bidi locale and at a R2L character the caret is moved to the
 * end of the R2L segment (visually left) and then one character to the
 * right (visually right because it's now in a L2R segment).
 */
void doVisualNext() {
    caretOffset = getClusterNext(caretOffset, getCaretLine());
    showCaret();
}
/**
 * Moves the caret to the end of the next word.
 * If a selection exists, move the caret to the end of the selection
 * and remove the selection.
 */
void doWordNext() {
    if (selection.y - selection.x > 0) {
        caretOffset = selection.y;
        showCaret();
    } else {
        doSelectionWordNext();
    }
}
/**
 * Moves the caret to the start of the previous word.
 * If a selection exists, move the caret to the start of the selection
 * and remove the selection.
 */
void doWordPrevious() {
    if (selection.y - selection.x > 0) {
        caretOffset = selection.x;
        showCaret();
    } else {
        doSelectionWordPrevious();
    }
}
/**
 * Ends the autoscroll process.
 */
void endAutoScroll() {
    autoScrollDirection = SWT.NULL;
}
public override Color getBackground() {
    checkWidget();
    if (background is null) {
        return getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND);
    }
    return background;
}
/**
 * Returns the baseline, in pixels.
 *
 * Note: this API should not be used if a StyleRange attribute causes lines to
 * have different heights (i.e. different fonts, rise, etc).
 *
 * @return baseline the baseline
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 3.0
 *
 * @see #getBaseline(int)
 */
public int getBaseline() {
    checkWidget();
    return renderer.getBaseline();
}
/**
 * Returns the baseline at the given offset, in pixels.
 *
 * @param offset the offset
 *
 * @return baseline the baseline
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the offset is outside the valid range (< 0 or > getCharCount())</li>
 * </ul>
 *
 * @since 3.2
 */
public int getBaseline(int offset) {
    checkWidget();
    if (!(0 <= offset && offset <= content.getCharCount())) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    if (isFixedLineHeight()) {
        return renderer.getBaseline();
    }
    int lineIndex = content.getLineAtOffset(offset);
    int lineOffset = content.getOffsetAtLine(lineIndex);
    TextLayout layout = renderer.getTextLayout(lineIndex);
    int lineInParagraph = layout.getLineIndex(Math.min(offset - lineOffset, layout.getText().length));
    FontMetrics metrics = layout.getLineMetrics(lineInParagraph);
    renderer.disposeTextLayout(layout);
    return metrics.getAscent() + metrics.getLeading();
}
/**
 * Gets the BIDI coloring mode.  When true the BIDI text display
 * algorithm is applied to segments of text that are the same
 * color.
 *
 * @return the current coloring mode
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @deprecated use BidiSegmentListener instead.
 */
public bool getBidiColoring() {
    checkWidget();
    return bidiColoring;
}
/**
 * Returns the index of the last fully visible line.
 *
 * @return index of the last fully visible line.
 */
int getBottomIndex() {
    int bottomIndex;
    if (isFixedLineHeight()) {
        int lineCount = 1;
        int lineHeight = renderer.getLineHeight();
        if (lineHeight !is 0) {
            // calculate the number of lines that are fully visible
            int partialTopLineHeight = topIndex * lineHeight - getVerticalScrollOffset();
            lineCount = (clientAreaHeight - partialTopLineHeight) / lineHeight;
        }
        bottomIndex = Math.min(content.getLineCount() - 1, topIndex + Math.max(0, lineCount - 1));
    } else {
        int clientAreaHeight = this.clientAreaHeight - bottomMargin;
        bottomIndex = getLineIndex(clientAreaHeight);
        if (bottomIndex > 0) {
            int linePixel = getLinePixel(bottomIndex);
            int lineHeight = renderer.getLineHeight(bottomIndex);
            if (linePixel + lineHeight > clientAreaHeight) {
                if (getLinePixel(bottomIndex - 1) >= topMargin) {
                    bottomIndex--;
                }
            }
        }
    }
    return bottomIndex;
}
Rectangle getBoundsAtOffset(int offset) {
    int lineIndex = content.getLineAtOffset(offset);
    int lineOffset = content.getOffsetAtLine(lineIndex);
    String line = content.getLine(lineIndex);
    Rectangle bounds;
    if (line.length !is 0) {
        int offsetInLine = offset - lineOffset;
        TextLayout layout = renderer.getTextLayout(lineIndex);
        bounds = layout.getBounds(offsetInLine, offsetInLine);
        renderer.disposeTextLayout(layout);
    } else {
        bounds = new Rectangle (0, 0, 0, renderer.getLineHeight());
    }
    if (offset is caretOffset) {
        int lineEnd = lineOffset + line.length;
        if (offset is lineEnd && caretAlignment is PREVIOUS_OFFSET_TRAILING) {
            bounds.width += getCaretWidth();
        }
    }
    bounds.x += leftMargin - horizontalScrollOffset;
    bounds.y += getLinePixel(lineIndex);
    return bounds;
}
/**
 * Returns the caret position relative to the start of the text.
 *
 * @return the caret position relative to the start of the text.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getCaretOffset() {
    checkWidget();
    return caretOffset;
}
/**
 * Returns the caret width.
 *
 * @return the caret width, 0 if caret is null.
 */
int getCaretWidth() {
    Caret caret = getCaret();
    if (caret is null) return 0;
    return caret.getSize().x;
}
Object getClipboardContent(int clipboardType) {
    TextTransfer plainTextTransfer = TextTransfer.getInstance();
    return clipboard.getContents(plainTextTransfer, clipboardType);
}
int getClusterNext(int offset, int lineIndex) {
    int lineOffset = content.getOffsetAtLine(lineIndex);
    TextLayout layout = renderer.getTextLayout(lineIndex);
    offset -= lineOffset;
    offset = layout.getNextOffset(offset, SWT.MOVEMENT_CLUSTER);
    offset += lineOffset;
    renderer.disposeTextLayout(layout);
    return offset;
}
int getClusterPrevious(int offset, int lineIndex) {
    int lineOffset = content.getOffsetAtLine(lineIndex);
    TextLayout layout = renderer.getTextLayout(lineIndex);
    offset -= lineOffset;
    offset = layout.getPreviousOffset(offset, SWT.MOVEMENT_CLUSTER);
    offset += lineOffset;
    renderer.disposeTextLayout(layout);
    return offset;
}
/**
 * Returns the content implementation that is used for text storage.
 *
 * @return content the user defined content implementation that is used for
 * text storage or the default content implementation if no user defined
 * content implementation has been set.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public StyledTextContent getContent() {
    checkWidget();
    return content;
}
public override bool getDragDetect () {
    checkWidget ();
    return dragDetect_;
}
/**
 * Returns whether the widget implements double click mouse behavior.
 *
 * @return true if double clicking a word selects the word, false if double clicks
 * have the same effect as regular mouse clicks
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public bool getDoubleClickEnabled() {
    checkWidget();
    return doubleClickEnabled;
}
/**
 * Returns whether the widget content can be edited.
 *
 * @return true if content can be edited, false otherwise
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public bool getEditable() {
    checkWidget();
    return editable;
}
public override Color getForeground() {
    checkWidget();
    if (foreground is null) {
        return getDisplay().getSystemColor(SWT.COLOR_LIST_FOREGROUND);
    }
    return foreground;
}
/**
 * Returns the horizontal scroll increment.
 *
 * @return horizontal scroll increment.
 */
int getHorizontalIncrement() {
    return renderer.averageCharWidth;
}
/**
 * Returns the horizontal scroll offset relative to the start of the line.
 *
 * @return horizontal scroll offset relative to the start of the line,
 * measured in character increments starting at 0, if > 0 the content is scrolled
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getHorizontalIndex() {
    checkWidget();
    return horizontalScrollOffset / getHorizontalIncrement();
}
/**
 * Returns the horizontal scroll offset relative to the start of the line.
 *
 * @return the horizontal scroll offset relative to the start of the line,
 * measured in pixel starting at 0, if > 0 the content is scrolled.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getHorizontalPixel() {
    checkWidget();
    return horizontalScrollOffset;
}
/**
 * Returns the line indentation of the widget.
 *
 * @return the line indentation
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #getLineIndent(int)
 *
 * @since 3.2
 */
public int getIndent() {
    checkWidget();
    return indent;
}
/**
 * Returns whether the widget justifies lines.
 *
 * @return whether lines are justified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #getLineJustify(int)
 *
 * @since 3.2
 */
public bool getJustify() {
    checkWidget();
    return justify;
}
/**
 * Returns the action assigned to the key.
 * Returns SWT.NULL if there is no action associated with the key.
 *
 * @param key a key code defined in SWT.java or a character.
 *  Optionally ORd with a state mask.  Preferred state masks are one or more of
 *  SWT.MOD1, SWT.MOD2, SWT.MOD3, since these masks account for modifier platform
 *  differences.  However, there may be cases where using the specific state masks
 *  (i.e., SWT.CTRL, SWT.SHIFT, SWT.ALT, SWT.COMMAND) makes sense.
 * @return one of the predefined actions defined in ST.java or SWT.NULL
 *  if there is no action associated with the key.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getKeyBinding(int key) {
    checkWidget();
    if( auto p = key in keyActionMap ){
        return *p;
    }
    return SWT.NULL;
}
/**
 * Gets the number of characters.
 *
 * @return number of characters in the widget
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getCharCount() {
    checkWidget();
    return content.getCharCount();
}
/**
 * Returns the line at the given line index without delimiters.
 * Index 0 is the first line of the content. When there are not
 * any lines, getLine(0) is a valid call that answers an empty string.
 * <p>
 *
 * @param lineIndex index of the line to return.
 * @return the line text without delimiters
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the line index is outside the valid range (< 0 or >= getLineCount())</li>
 * </ul>
 * @since 3.4
 */
public String getLine(int lineIndex) {
    checkWidget();
    if (lineIndex < 0 ||
        (lineIndex > 0 && lineIndex >= content.getLineCount())) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return content.getLine(lineIndex);
}
/**
 * Returns the alignment of the line at the given index.
 *
 * @param index the index of the line
 *
 * @return the line alignment
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
 * </ul>
 *
 * @see #getAlignment()
 *
 * @since 3.2
 */
public int getLineAlignment(int index) {
    checkWidget();
    if (index < 0 || index > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return renderer.getLineAlignment(index, alignment);
}
/**
 * Returns the line at the specified offset in the text
 * where 0 &lt; offset &lt; getCharCount() so that getLineAtOffset(getCharCount())
 * returns the line of the insert location.
 *
 * @param offset offset relative to the start of the content.
 *  0 <= offset <= getCharCount()
 * @return line at the specified offset in the text
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the offset is outside the valid range (< 0 or > getCharCount())</li>
 * </ul>
 */
public int getLineAtOffset(int offset) {
    checkWidget();
    if (offset < 0 || offset > getCharCount()) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return content.getLineAtOffset(offset);
}
/**
 * Returns the background color of the line at the given index.
 * Returns null if a LineBackgroundListener has been set or if no background
 * color has been specified for the line. Should not be called if a
 * LineBackgroundListener has been set since the listener maintains the
 * line background colors.
 *
 * @param index the index of the line
 * @return the background color of the line at the given index.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
 * </ul>
 */
public Color getLineBackground(int index) {
    checkWidget();
    if (index < 0 || index > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return isListening(LineGetBackground) ? null : renderer.getLineBackground(index, null);
}
/**
 * Returns the bullet of the line at the given index.
 *
 * @param index the index of the line
 *
 * @return the line bullet
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
 * </ul>
 *
 * @since 3.2
 */
public Bullet getLineBullet(int index) {
    checkWidget();
    if (index < 0 || index > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return isListening(LineGetStyle) ? null : renderer.getLineBullet(index, null);
}
/**
 * Returns the line background data for the given line or null if
 * there is none.
 *
 * @param lineOffset offset of the line start relative to the start
 *  of the content.
 * @param line line to get line background data for
 * @return line background data for the given line.
 */
StyledTextEvent getLineBackgroundData(int lineOffset, String line) {
    return sendLineEvent(LineGetBackground, lineOffset, line);
}
/**
 * Gets the number of text lines.
 *
 * @return the number of lines in the widget
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getLineCount() {
    checkWidget();
    return content.getLineCount();
}
/**
 * Returns the number of lines that can be completely displayed in the
 * widget client area.
 *
 * @return number of lines that can be completely displayed in the widget
 *  client area.
 */
int getLineCountWhole() {
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        return lineHeight !is 0 ? clientAreaHeight / lineHeight : 1;
    }
    return getBottomIndex() - topIndex + 1;
}
/**
 * Returns the line delimiter used for entering new lines by key down
 * or paste operation.
 *
 * @return line delimiter used for entering new lines by key down
 * or paste operation.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getLineDelimiter() {
    checkWidget();
    return content.getLineDelimiter();
}
/**
 * Returns the line height.
 * <p>
 * Note: this API should not be used if a StyleRange attribute causes lines to
 * have different heights (i.e. different fonts, rise, etc).
 * </p>
 *
 * @return line height in pixel.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @see #getLineHeight(int)
 */
public int getLineHeight() {
    checkWidget();
    return renderer.getLineHeight();
}
/**
 * Returns the line height at the given offset.
 *
 * @param offset the offset
 *
 * @return line height in pixels
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the offset is outside the valid range (< 0 or > getCharCount())</li>
 * </ul>
 *
 * @since 3.2
 */
public int getLineHeight(int offset) {
    checkWidget();
    if (!(0 <= offset && offset <= content.getCharCount())) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    if (isFixedLineHeight()) {
        return renderer.getLineHeight();
    }
    int lineIndex = content.getLineAtOffset(offset);
    int lineOffset = content.getOffsetAtLine(lineIndex);
    TextLayout layout = renderer.getTextLayout(lineIndex);
    int lineInParagraph = layout.getLineIndex(Math.min(offset - lineOffset, layout.getText().length));
    int height = layout.getLineBounds(lineInParagraph).height;
    renderer.disposeTextLayout(layout);
    return height;
}
/**
 * Returns the indentation of the line at the given index.
 *
 * @param index the index of the line
 *
 * @return the line indentation
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
 * </ul>
 *
 * @see #getIndent()
 *
 * @since 3.2
 */
public int getLineIndent(int index) {
    checkWidget();
    if (index < 0 || index > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return isListening(LineGetStyle) ? 0 : renderer.getLineIndent(index, indent);
}
/**
 * Returns whether the line at the given index is justified.
 *
 * @param index the index of the line
 *
 * @return whether the line is justified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT when the index is invalid</li>
 * </ul>
 *
 * @see #getJustify()
 *
 * @since 3.2
 */
public bool getLineJustify(int index) {
    checkWidget();
    if (index < 0 || index > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return isListening(LineGetStyle) ? false : renderer.getLineJustify(index, justify);
}
/**
 * Returns the line spacing of the widget.
 *
 * @return the line spacing
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 3.2
 */
public int getLineSpacing() {
    checkWidget();
    return lineSpacing;
}
/**
 * Returns the line style data for the given line or null if there is
 * none.
 * <p>
 * If there is a LineStyleListener but it does not set any styles,
 * the StyledTextEvent.styles field will be initialized to an empty
 * array.
 * </p>
 *
 * @param lineOffset offset of the line start relative to the start of
 *  the content.
 * @param line line to get line styles for
 * @return line style data for the given line. Styles may start before
 *  line start and end after line end
 */
StyledTextEvent getLineStyleData(int lineOffset, String line) {
    return sendLineEvent(LineGetStyle, lineOffset, line);
}
/**
 * Returns the top pixel, relative to the client area, of a given line.
 * Clamps out of ranges index.
 *
 * @param lineIndex the line index, the max value is lineCount. If
 * lineIndex is lineCount it returns the bottom pixel of the last line.
 * It means this function can be used to retrieve the bottom pixel of any line.
 *
 * @return the top pixel of a given line index
 *
 * @since 3.2
 */
public int getLinePixel(int lineIndex) {
    checkWidget();
    int lineCount = content.getLineCount();
    lineIndex = Math.max(0, Math.min(lineCount, lineIndex));
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        return lineIndex * lineHeight - getVerticalScrollOffset() + topMargin;
    }
    if (lineIndex is topIndex) return topIndexY + topMargin;
    int height = topIndexY;
    if (lineIndex > topIndex) {
        for (int i = topIndex; i < lineIndex; i++) {
            height += renderer.getLineHeight(i);
        }
    } else {
        for (int i = topIndex - 1; i >= lineIndex; i--) {
            height -= renderer.getLineHeight(i);
        }
    }
    return height + topMargin;
}
/**
 * Returns the line index for a y, relative to the client area.
 * The line index returned is always in the range 0..lineCount - 1.
 *
 * @param y the y-coordinate pixel
 *
 * @return the line index for a given y-coordinate pixel
 *
 * @since 3.2
 */
public int getLineIndex(int y) {
    checkWidget();
    y -= topMargin;
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        int lineIndex = (y + getVerticalScrollOffset()) / lineHeight;
        int lineCount = content.getLineCount();
        lineIndex = Math.max(0, Math.min(lineCount - 1, lineIndex));
        return lineIndex;
    }
    if (y is topIndexY) return topIndex;
    int line = topIndex;
    if (y < topIndexY) {
        while (y < topIndexY && line > 0) {
            y += renderer.getLineHeight(--line);
        }
    } else {
        int lineCount = content.getLineCount();
        int lineHeight = renderer.getLineHeight(line);
        while (y - lineHeight >= topIndexY && line < lineCount - 1) {
            y -= lineHeight;
            lineHeight = renderer.getLineHeight(++line);
        }
    }
    return line;
}
/**
 * Returns the x, y location of the upper left corner of the character
 * bounding box at the specified offset in the text. The point is
 * relative to the upper left corner of the widget client area.
 *
 * @param offset offset relative to the start of the content.
 *  0 <= offset <= getCharCount()
 * @return x, y location of the upper left corner of the character
 *  bounding box at the specified offset in the text.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the offset is outside the valid range (< 0 or > getCharCount())</li>
 * </ul>
 */
public Point getLocationAtOffset(int offset) {
    checkWidget();
    if (offset < 0 || offset > getCharCount()) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return getPointAtOffset(offset);
}
/**
 * Returns the character offset of the first character of the given line.
 *
 * @param lineIndex index of the line, 0 based relative to the first
 *  line in the content. 0 <= lineIndex < getLineCount(), except
 *  lineIndex may always be 0
 * @return offset offset of the first character of the line, relative to
 *  the beginning of the document. The first character of the document is
 *  at offset 0.
 *  When there are not any lines, getOffsetAtLine(0) is a valid call that
 *  answers 0.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the line index is outside the valid range (< 0 or >= getLineCount())</li>
 * </ul>
 * @since 2.0
 */
public int getOffsetAtLine(int lineIndex) {
    checkWidget();
    if (lineIndex < 0 ||
        (lineIndex > 0 && lineIndex >= content.getLineCount())) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return content.getOffsetAtLine(lineIndex);
}
/**
 * Returns the offset of the character at the given location relative
 * to the first character in the document.
 * <p>
 * The return value reflects the character offset that the caret will
 * be placed at if a mouse click occurred at the specified location.
 * If the x coordinate of the location is beyond the center of a character
 * the returned offset will be behind the character.
 * </p>
 *
 * @param point the origin of character bounding box relative to
 *  the origin of the widget client area.
 * @return offset of the character at the given location relative
 *  to the first character in the document.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_NULL_ARGUMENT when point is null</li>
 *   <li>ERROR_INVALID_ARGUMENT when there is no character at the specified location</li>
 * </ul>
 */
public int getOffsetAtLocation(Point point) {
    checkWidget();
    if (point is null) {
        SWT.error(SWT.ERROR_NULL_ARGUMENT);
    }
    int[] trailing = new int[1];
    int offset = getOffsetAtPoint(point.x, point.y, trailing, true);
    if (offset is -1) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    return offset + trailing[0];
}
int getOffsetAtPoint(int x, int y) {
    int lineIndex = getLineIndex(y);
    y -= getLinePixel(lineIndex);
    return getOffsetAtPoint(x, y, lineIndex);
}
/**
 * Returns the offset at the specified x location in the specified line.
 *
 * @param x x location of the mouse location
 * @param line  line the mouse location is in
 * @return the offset at the specified x location in the specified line,
 *  relative to the beginning of the document
 */
int getOffsetAtPoint(int x, int y, int lineIndex) {
    TextLayout layout = renderer.getTextLayout(lineIndex);
    x += horizontalScrollOffset - leftMargin;
    int[1] trailing;
    int offsetInLine = layout.getOffset(x, y, trailing);
    caretAlignment = OFFSET_LEADING;
    if (trailing[0] !is 0) {
        int lineInParagraph = layout.getLineIndex(offsetInLine + trailing[0]);
        int lineStart = layout.getLineOffsets()[lineInParagraph];
        if (offsetInLine + trailing[0] is lineStart) {
            offsetInLine += trailing[0];
            caretAlignment = PREVIOUS_OFFSET_TRAILING;
        } else {
            String line = content.getLine(lineIndex);
            int level;
            int offset = offsetInLine;
            while (offset > 0 && Character.isDigit(line.dcharAt(offset))) offset--;
            if (offset is 0 && Character.isDigit(line.dcharAt(offset))) {
                level = isMirrored() ? 1 : 0;
            } else {
                level = layout.getLevel(offset) & 0x1;
            }
            offsetInLine += trailing[0];
            int trailingLevel = layout.getLevel(offsetInLine) & 0x1;
            if ((level ^ trailingLevel) !is 0) {
                caretAlignment = PREVIOUS_OFFSET_TRAILING;
            } else {
                caretAlignment = OFFSET_LEADING;
            }
        }
    }
    renderer.disposeTextLayout(layout);
    return offsetInLine + content.getOffsetAtLine(lineIndex);
}
int getOffsetAtPoint(int x, int y, int[] trailing, bool inTextOnly) {
    if (inTextOnly && y + getVerticalScrollOffset() < 0 || x + horizontalScrollOffset < 0) {
        return -1;
    }
    int bottomIndex = getPartialBottomIndex();
    int height = getLinePixel(bottomIndex + 1);
    if (inTextOnly && y > height) {
        return -1;
    }
    int lineIndex = getLineIndex(y);
    int lineOffset = content.getOffsetAtLine(lineIndex);
    TextLayout layout = renderer.getTextLayout(lineIndex);
    x += horizontalScrollOffset - leftMargin ;
    y -= getLinePixel(lineIndex);
    int offset = layout.getOffset(x, y, trailing);
    Rectangle rect = layout.getLineBounds(layout.getLineIndex(offset));
    renderer.disposeTextLayout(layout);
    if (inTextOnly && !(rect.x  <= x && x <=  rect.x + rect.width)) {
        return -1;
    }
    return offset + lineOffset;
}
/**
 * Returns the orientation of the receiver.
 *
 * @return the orientation style
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 2.1.2
 */
public int getOrientation () {
    checkWidget();
    return isMirrored() ? SWT.RIGHT_TO_LEFT : SWT.LEFT_TO_RIGHT;
}
/**
 * Returns the index of the last partially visible line.
 *
 * @return index of the last partially visible line.
 */
int getPartialBottomIndex() {
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        int partialLineCount = Compatibility.ceil(clientAreaHeight, lineHeight);
        return Math.max(0, Math.min(content.getLineCount(), topIndex + partialLineCount) - 1);
    }
    return getLineIndex(clientAreaHeight - bottomMargin);
}
/**
 * Returns the index of the first partially visible line.
 *
 * @return index of the first partially visible line.
 */
int getPartialTopIndex() {
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        return getVerticalScrollOffset() / lineHeight;
    }
    return topIndexY <= 0 ? topIndex : topIndex - 1;
}
/**
 * Returns the content in the specified range using the platform line
 * delimiter to separate lines.
 *
 * @param writer the TextWriter to write line text into
 * @return the content in the specified range using the platform line
 *  delimiter to separate lines as written by the specified TextWriter.
 */
String getPlatformDelimitedText(TextWriter writer) {
    int end = writer.getStart() + writer.getCharCount();
    int startLine = content.getLineAtOffset(writer.getStart());
    int endLine = content.getLineAtOffset(end);
    String endLineText = content.getLine(endLine);
    int endLineOffset = content.getOffsetAtLine(endLine);

    for (int i = startLine; i <= endLine; i++) {
        writer.writeLine(content.getLine(i), content.getOffsetAtLine(i));
        if (i < endLine) {
            writer.writeLineDelimiter(PlatformLineDelimiter);
        }
    }
    if (end > endLineOffset + endLineText.length) {
        writer.writeLineDelimiter(PlatformLineDelimiter);
    }
    writer.close();
    return writer.toString();
}
/**
 * Returns all the ranges of text that have an associated StyleRange.
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * <p>
 * The ranges array contains start and length pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] with length ranges[n+1] uses the style
 * at styles[n/2] returned by <code>getStyleRanges(int, int, bool)</code>.
 * </p>
 *
 * @return the ranges or an empty array if a LineStyleListener has been set.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 3.2
 *
 * @see #getStyleRanges(bool)
 */
public int[] getRanges() {
    checkWidget();
    if (!isListening(LineGetStyle)) {
        int[] ranges = renderer.getRanges(0, content.getCharCount());
        if (ranges !is null) return ranges;
    }
    return new int[0];
}
/**
 * Returns the ranges of text that have an associated StyleRange.
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * <p>
 * The ranges array contains start and length pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] with length ranges[n+1] uses the style
 * at styles[n/2] returned by <code>getStyleRanges(int, int, bool)</code>.
 * </p>
 *
 * @param start the start offset of the style ranges to return
 * @param length the number of style ranges to return
 *
 * @return the ranges or an empty array if a LineStyleListener has been set.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE if start or length are outside the widget content</li>
 * </ul>
 *
 * @since 3.2
 *
 * @see #getStyleRanges(int, int, bool)
 */
public int[] getRanges(int start, int length) {
    checkWidget();
    int contentLength = getCharCount();
    int end = start + length;
    if (start > end || start < 0 || end > contentLength) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    if (!isListening(LineGetStyle)) {
        int[] ranges = renderer.getRanges(start, length);
        if (ranges !is null) return ranges;
    }
    return new int[0];
}
/**
 * Returns the selection.
 * <p>
 * Text selections are specified in terms of caret positions.  In a text
 * widget that contains N characters, there are N+1 caret positions,
 * ranging from 0..N
 * </p>
 *
 * @return start and end of the selection, x is the offset of the first
 *  selected character, y is the offset after the last selected character.
 *  The selection values returned are visual (i.e., x will always always be
 *  <= y).  To determine if a selection is right-to-left (RtoL) vs. left-to-right
 *  (LtoR), compare the caretOffset to the start and end of the selection
 *  (e.g., caretOffset is start of selection implies that the selection is RtoL).
 * @see #getSelectionRange
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Point getSelection() {
    checkWidget();
    return new Point(selection.x, selection.y);
}
/**
 * Returns the selection.
 *
 * @return start and length of the selection, x is the offset of the
 *  first selected character, relative to the first character of the
 *  widget content. y is the length of the selection.
 *  The selection values returned are visual (i.e., length will always always be
 *  positive).  To determine if a selection is right-to-left (RtoL) vs. left-to-right
 *  (LtoR), compare the caretOffset to the start and end of the selection
 *  (e.g., caretOffset is start of selection implies that the selection is RtoL).
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Point getSelectionRange() {
    checkWidget();
    return new Point(selection.x, selection.y - selection.x);
}
/**
 * Returns the receiver's selection background color.
 *
 * @return the selection background color
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.1
 */
public Color getSelectionBackground() {
    checkWidget();
    if (selectionBackground is null) {
        return getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION);
    }
    return selectionBackground;
}
/**
 * Gets the number of selected characters.
 *
 * @return the number of selected characters.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getSelectionCount() {
    checkWidget();
    return getSelectionRange().y;
}
/**
 * Returns the receiver's selection foreground color.
 *
 * @return the selection foreground color
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.1
 */
public Color getSelectionForeground() {
    checkWidget();
    if (selectionForeground is null) {
        return getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT);
    }
    return selectionForeground;
}
/**
 * Returns the selected text.
 *
 * @return selected text, or an empty String if there is no selection.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getSelectionText() {
    checkWidget();
    return content.getTextRange(selection.x, selection.y - selection.x);
}
public override int getStyle() {
    int style = super.getStyle();
    style &= ~(SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT | SWT.MIRRORED);
    if (isMirrored()) {
        style |= SWT.RIGHT_TO_LEFT | SWT.MIRRORED;
    } else {
        style |= SWT.LEFT_TO_RIGHT;
    }
    return style;
}

/**
 * Returns the text segments that should be treated as if they
 * had a different direction than the surrounding text.
 *
 * @param lineOffset offset of the first character in the line.
 *  0 based from the beginning of the document.
 * @param line text of the line to specify bidi segments for
 * @return text segments that should be treated as if they had a
 *  different direction than the surrounding text. Only the start
 *  index of a segment is specified, relative to the start of the
 *  line. Always starts with 0 and ends with the line length.
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the segment indices returned
 *      by the listener do not start with 0, are not in ascending order,
 *      exceed the line length or have duplicates</li>
 * </ul>
 */
int [] getBidiSegments(int lineOffset, String line) {
    if (!isBidi()) return null;
    if (!isListening(LineGetSegments)) {
        return getBidiSegmentsCompatibility(line, lineOffset);
    }
    StyledTextEvent event = sendLineEvent(LineGetSegments, lineOffset, line);
    int lineLength = line.length;
    int[] segments;
    if (event is null || event.segments is null || event.segments.length is 0) {
        segments = [0, lineLength];
    } else {
        int segmentCount = event.segments.length;

        // test segment index consistency
        if (event.segments[0] !is 0) {
            SWT.error(SWT.ERROR_INVALID_ARGUMENT);
        }
        for (int i = 1; i < segmentCount; i++) {
            if (event.segments[i] <= event.segments[i - 1] || event.segments[i] > lineLength) {
                SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            }
        }
        // ensure that last segment index is line end offset
        if (event.segments[segmentCount - 1] !is lineLength) {
            segments = new int[segmentCount + 1];
            System.arraycopy(event.segments, 0, segments, 0, segmentCount);
            segments[segmentCount] = lineLength;
        } else {
            segments = event.segments;
        }
    }
    return segments;
}
/**
 * @see #getBidiSegments
 * Supports deprecated setBidiColoring API. Remove when API is removed.
 */
int [] getBidiSegmentsCompatibility(String line, int lineOffset) {
    int lineLength = line.length;
    if (!bidiColoring) {
        return [0, lineLength];
    }
    StyleRange [] styles = null;
    StyledTextEvent event = getLineStyleData(lineOffset, line);
    if (event !is null) {
        styles = event.styles;
    } else {
        styles = renderer.getStyleRanges(lineOffset, lineLength, true);
    }
    if (styles is null || styles.length is 0) {
        return [0, lineLength];
    }
    int k=0, count = 1;
    while (k < styles.length && styles[k].start is 0 && styles[k].length is lineLength) {
        k++;
    }
    int[] offsets = new int[(styles.length - k) * 2 + 2];
    for (int i = k; i < styles.length; i++) {
        StyleRange style = styles[i];
        int styleLineStart = Math.max(style.start - lineOffset, 0);
        int styleLineEnd = Math.max(style.start + style.length - lineOffset, styleLineStart);
        styleLineEnd = Math.min (styleLineEnd, line.length );
        if (i > 0 && count > 1 &&
            ((styleLineStart >= offsets[count-2] && styleLineStart <= offsets[count-1]) ||
             (styleLineEnd >= offsets[count-2] && styleLineEnd <= offsets[count-1])) &&
             style.similarTo(styles[i-1])) {
            offsets[count-2] = Math.min(offsets[count-2], styleLineStart);
            offsets[count-1] = Math.max(offsets[count-1], styleLineEnd);
        } else {
            if (styleLineStart > offsets[count - 1]) {
                offsets[count] = styleLineStart;
                count++;
            }
            offsets[count] = styleLineEnd;
            count++;
        }
    }
    // add offset for last non-colored segment in line, if any
    if (lineLength > offsets[count-1]) {
        offsets [count] = lineLength;
        count++;
    }
    if (count is offsets.length) {
        return offsets;
    }
    int [] result = new int [count];
    System.arraycopy (offsets, 0, result, 0, count);
    return result;
}
/**
 * Returns the style range at the given offset.
 * <p>
 * Returns null if a LineStyleListener has been set or if a style is not set
 * for the offset.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param offset the offset to return the style for.
 *  0 <= offset < getCharCount() must be true.
 * @return a StyleRange with start is offset and length is 1, indicating
 *  the style at the given offset. null if a LineStyleListener has been set
 *  or if a style is not set for the given offset.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the offset is invalid</li>
 * </ul>
 */
public StyleRange getStyleRangeAtOffset(int offset) {
    checkWidget();
    if (offset < 0 || offset >= getCharCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    if (!isListening(LineGetStyle)) {
        StyleRange[] ranges = renderer.getStyleRanges(offset, 1, true);
        if (ranges !is null) return ranges[0];
    }
    return null;
}
/**
 * Returns the styles.
 * <p>
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * <p></p>
 * Note: Because a StyleRange includes the start and length, the
 * same instance cannot occur multiple times in the array of styles.
 * If the same style attributes, such as font and color, occur in
 * multiple StyleRanges, <code>getStyleRanges(bool)</code>
 * can be used to get the styles without the ranges.
 * </p>
 *
 * @return the styles or an empty array if a LineStyleListener has been set.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #getStyleRanges(bool)
 */
public StyleRange[] getStyleRanges() {
    checkWidget();
    return getStyleRanges(0, content.getCharCount(), true);
}
/**
 * Returns the styles.
 * <p>
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p><p>
 * Note: When <code>includeRanges</code> is true, the start and length
 * fields of each StyleRange will be valid, however the StyleRange
 * objects may need to be cloned. When <code>includeRanges</code> is
 * false, <code>getRanges(int, int)</code> can be used to get the
 * associated ranges.
 * </p>
 *
 * @param includeRanges whether the start and length field of the StyleRanges should be set.
 *
 * @return the styles or an empty array if a LineStyleListener has been set.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 3.2
 *
 * @see #getRanges(int, int)
 * @see #setStyleRanges(int[], StyleRange[])
 */
public StyleRange[] getStyleRanges(bool includeRanges) {
    checkWidget();
    return getStyleRanges(0, content.getCharCount(), includeRanges);
}
/**
 * Returns the styles for the given text range.
 * <p>
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p><p>
 * Note: Because the StyleRange includes the start and length, the
 * same instance cannot occur multiple times in the array of styles.
 * If the same style attributes, such as font and color, occur in
 * multiple StyleRanges, <code>getStyleRanges(int, int, bool)</code>
 * can be used to get the styles without the ranges.
 * </p>
 * @param start the start offset of the style ranges to return
 * @param length the number of style ranges to return
 *
 * @return the styles or an empty array if a LineStyleListener has
 *  been set.  The returned styles will reflect the given range.  The first
 *  returned <code>StyleRange</code> will have a starting offset >= start
 *  and the last returned <code>StyleRange</code> will have an ending
 *  offset <= start + length - 1
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or end are outside the widget content</li>
 * </ul>
 *
 * @see #getStyleRanges(int, int, bool)
 *
 * @since 3.0
 */
public StyleRange[] getStyleRanges(int start, int length) {
    checkWidget();
    return getStyleRanges(start, length, true);
}
/**
 * Returns the styles for the given text range.
 * <p>
 * Returns an empty array if a LineStyleListener has been set.
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p><p>
 * Note: When <code>includeRanges</code> is true, the start and length
 * fields of each StyleRange will be valid, however the StyleRange
 * objects may need to be cloned. When <code>includeRanges</code> is
 * false, <code>getRanges(int, int)</code> can be used to get the
 * associated ranges.
 * </p>
 *
 * @param start the start offset of the style ranges to return
 * @param length the number of style ranges to return
 * @param includeRanges whether the start and length field of the StyleRanges should be set.
 *
 * @return the styles or an empty array if a LineStyleListener has
 *  been set.  The returned styles will reflect the given range.  The first
 *  returned <code>StyleRange</code> will have a starting offset >= start
 *  and the last returned <code>StyleRange</code> will have an ending
 *  offset <= start + length - 1
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or end are outside the widget content</li>
 * </ul>
 *
 * @since 3.2
 *
 * @see #getRanges(int, int)
 * @see #setStyleRanges(int[], StyleRange[])
 */
public StyleRange[] getStyleRanges(int start, int length, bool includeRanges) {
    checkWidget();
    int contentLength = getCharCount();
    int end = start + length;
    if (start > end || start < 0 || end > contentLength) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    if (!isListening(LineGetStyle)) {
        StyleRange[] ranges = renderer.getStyleRanges(start, length, includeRanges);
        if (ranges !is null) return ranges;
    }
    return new StyleRange[0];
}
/**
 * Returns the tab width measured in characters.
 *
 * @return tab width measured in characters
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getTabs() {
    checkWidget();
    return tabLength;
}
/**
 * Returns a copy of the widget content.
 *
 * @return copy of the widget content
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public String getText() {
    checkWidget();
    return content.getTextRange(0, getCharCount());
}
/**
 * Returns the widget content between the two offsets.
 *
 * @param start offset of the first character in the returned String
 * @param end offset of the last character in the returned String
 * @return widget content starting at start and ending at end
 * @see #getTextRange(int,int)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or end are outside the widget content</li>
 * </ul>
 */
public String getText(int start, int end) {
    checkWidget();
    int contentLength = getCharCount();
    if (start < 0 || start >= contentLength || end < 0 || end >= contentLength || start > end) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return content.getTextRange(start, end - start + 1);
}
/**
 * Returns the smallest bounding rectangle that includes the characters between two offsets.
 *
 * @param start offset of the first character included in the bounding box
 * @param end offset of the last character included in the bounding box
 * @return bounding box of the text between start and end
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or end are outside the widget content</li>
 * </ul>
 * @since 3.1
 */
public Rectangle getTextBounds(int start, int end) {
    checkWidget();
    int contentLength = getCharCount();
    if (start < 0 || start >= contentLength || end < 0 || end >= contentLength || start > end) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    int lineStart = content.getLineAtOffset(start);
    int lineEnd = content.getLineAtOffset(end);
    Rectangle rect;
    int y = getLinePixel(lineStart);
    int height = 0;
    int left = 0x7fffffff, right = 0;
    for (int i = lineStart; i <= lineEnd; i++) {
        int lineOffset = content.getOffsetAtLine(i);
        TextLayout layout = renderer.getTextLayout(i);
        int length = layout.getText().length;
        if (length > 0) {
            if (i is lineStart) {
                if (i is lineEnd) {
                    rect = layout.getBounds(start - lineOffset, end - lineOffset);
                } else {
                    rect = layout.getBounds(start - lineOffset, length);
                }
                y += rect.y;
            } else if (i is lineEnd) {
                rect = layout.getBounds(0, end - lineOffset);
            } else {
                rect = layout.getBounds();
            }
            left = Math.min(left, rect.x);
            right = Math.max(right, rect.x + rect.width);
            height += rect.height;
        } else {
            height += renderer.getLineHeight();
        }
        renderer.disposeTextLayout(layout);
    }
    rect = new Rectangle (left, y, right-left, height);
    rect.x += leftMargin - horizontalScrollOffset;
    return rect;
}
/**
 * Returns the widget content starting at start for length characters.
 *
 * @param start offset of the first character in the returned String
 * @param length number of characters to return
 * @return widget content starting at start and extending length characters.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or length are outside the widget content</li>
 * </ul>
 */
public String getTextRange(int start, int length) {
    checkWidget();
    int contentLength = getCharCount();
    int end = start + length;
    if (start > end || start < 0 || end > contentLength) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    return content.getTextRange(start, length);
}
/**
 * Returns the maximum number of characters that the receiver is capable of holding.
 *
 * @return the text limit
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getTextLimit() {
    checkWidget();
    return textLimit;
}
/**
 * Gets the top index.
 * <p>
 * The top index is the index of the fully visible line that is currently
 * at the top of the widget or the topmost partially visible line if no line is fully visible.
 * The top index changes when the widget is scrolled. Indexing is zero based.
 * </p>
 *
 * @return the index of the top line
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getTopIndex() {
    checkWidget();
    return topIndex;
}
/**
 * Gets the top pixel.
 * <p>
 * The top pixel is the pixel position of the line that is
 * currently at the top of the widget. The text widget can be scrolled by pixels
 * by dragging the scroll thumb so that a partial line may be displayed at the top
 * the widget.  The top pixel changes when the widget is scrolled.  The top pixel
 * does not include the widget trimming.
 * </p>
 *
 * @return pixel position of the top line
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getTopPixel() {
    checkWidget();
    return getVerticalScrollOffset();
}
/**
 * Returns the vertical scroll increment.
 *
 * @return vertical scroll increment.
 */
int getVerticalIncrement() {
    return renderer.getLineHeight();
}
int getVerticalScrollOffset() {
    if (verticalScrollOffset is -1) {
        renderer.calculate(0, topIndex);
        int height = 0;
        for (int i = 0; i < topIndex; i++) {
            height += renderer.getLineHeight(i);
        }
        height -= topIndexY;
        verticalScrollOffset = height;
    }
    return verticalScrollOffset;
}
int getVisualLineIndex(TextLayout layout, int offsetInLine) {
    int lineIndex = layout.getLineIndex(offsetInLine);
    int[] offsets = layout.getLineOffsets();
    if (lineIndex !is 0 && offsetInLine is offsets[lineIndex]) {
        int lineY = layout.getLineBounds(lineIndex).y;
        int caretY = getCaret().getLocation().y - topMargin - getLinePixel(getCaretLine());
        if (lineY > caretY) lineIndex--;
    }
    return lineIndex;
}
int getCaretDirection() {
    if (!isBidiCaret()) return SWT.DEFAULT;
    if (ime.getCompositionOffset() !is -1) return SWT.DEFAULT;
    if (!updateCaretDirection && caretDirection !is SWT.NULL) return caretDirection;
    updateCaretDirection = false;
    int caretLine = getCaretLine();
    int lineOffset = content.getOffsetAtLine(caretLine);
    String line = content.getLine(caretLine);
    int offset = caretOffset - lineOffset;
    int lineLength = line.length;
    if (lineLength is 0) return isMirrored() ? SWT.RIGHT : SWT.LEFT;
    if (caretAlignment is PREVIOUS_OFFSET_TRAILING && offset > 0) offset--;
    if (offset is lineLength && offset > 0) offset--;
    while (offset > 0 && Character.isDigit(line.dcharAt(offset))) offset--;
    if (offset is 0 && Character.isDigit(line.dcharAt(offset))) {
        return isMirrored() ? SWT.RIGHT : SWT.LEFT;
    }
    TextLayout layout = renderer.getTextLayout(caretLine);
    int level = layout.getLevel(offset);
    renderer.disposeTextLayout(layout);
    return ((level & 1) !is 0) ? SWT.RIGHT : SWT.LEFT;
}
/*
 * Returns the index of the line the caret is on.
 */
int getCaretLine() {
    return content.getLineAtOffset(caretOffset);
}
int getWrapWidth () {
    if (wordWrap && !isSingleLine()) {
        int width = clientAreaWidth - leftMargin - rightMargin - getCaretWidth();
        return width > 0 ? width : 1;
    }
    return -1;
}
int getWordNext (int offset, int movement) {
    int newOffset, lineOffset;
    String lineText;
    if (offset >= getCharCount()) {
        newOffset = offset;
        int lineIndex = content.getLineCount() - 1;
        lineOffset = content.getOffsetAtLine(lineIndex);
        lineText = content.getLine(lineIndex);
    } else {
        int lineIndex = content.getLineAtOffset(offset);
        lineOffset = content.getOffsetAtLine(lineIndex);
        lineText = content.getLine(lineIndex);
        int lineLength = lineText.length;
        if (offset is lineOffset + lineLength) {
            newOffset = content.getOffsetAtLine(lineIndex + 1);
        } else {
            TextLayout layout = renderer.getTextLayout(lineIndex);
            newOffset = lineOffset + layout.getNextOffset(offset - lineOffset, movement);
            renderer.disposeTextLayout(layout);
        }
    }
    return sendWordBoundaryEvent(WordNext, movement, offset, newOffset, lineText, lineOffset);
}
int getWordPrevious(int offset, int movement) {
    int newOffset, lineOffset;
    String lineText;
    if (offset <= 0) {
        newOffset = 0;
        int lineIndex = content.getLineAtOffset(newOffset);
        lineOffset = content.getOffsetAtLine(lineIndex);
        lineText = content.getLine(lineIndex);
    } else {
        int lineIndex = content.getLineAtOffset(offset);
        lineOffset = content.getOffsetAtLine(lineIndex);
        lineText = content.getLine(lineIndex);
        if (offset is lineOffset) {
            String nextLineText = content.getLine(lineIndex - 1);
            int nextLineOffset = content.getOffsetAtLine(lineIndex - 1);
            newOffset = nextLineOffset + nextLineText.length;
        } else {
            TextLayout layout = renderer.getTextLayout(lineIndex);
            newOffset = lineOffset + layout.getPreviousOffset(offset - lineOffset, movement);
            renderer.disposeTextLayout(layout);
        }
    }
    return sendWordBoundaryEvent(WordPrevious, movement, offset, newOffset, lineText, lineOffset);
}
/**
 * Returns whether the widget wraps lines.
 *
 * @return true if widget wraps lines, false otherwise
 * @since 2.0
 */
public bool getWordWrap() {
    checkWidget();
    return wordWrap;
}
/**
 * Returns the location of the given offset.
 * <p>
 * <b>NOTE:</b> Does not return correct values for true italic fonts (vs. slanted fonts).
 * </p>
 *
 * @return location of the character at the given offset in the line.
 */
Point getPointAtOffset(int offset) {
    int lineIndex = content.getLineAtOffset(offset);
    String line = content.getLine(lineIndex);
    int lineOffset = content.getOffsetAtLine(lineIndex);
    int offsetInLine = offset - lineOffset;
    int lineLength = line.length;
    if (lineIndex < content.getLineCount() - 1) {
        int endLineOffset = content.getOffsetAtLine(lineIndex + 1) - 1;
        if (lineLength < offsetInLine && offsetInLine <= endLineOffset) {
            offsetInLine = lineLength;
        }
    }
    Point point;
    TextLayout layout = renderer.getTextLayout(lineIndex);
    if (lineLength !is 0  && offsetInLine <= lineLength) {
        if (offsetInLine is lineLength) {
            // SWT: Instead of go back one byte, go back one codepoint
            int offsetInLine_m1 = layout.getPreviousOffset(offsetInLine, SWT.MOVEMENT_CLUSTER);
            point = layout.getLocation(offsetInLine_m1, true);
        } else {
            switch (caretAlignment) {
                case OFFSET_LEADING:
                    point = layout.getLocation(offsetInLine, false);
                    break;
                case PREVIOUS_OFFSET_TRAILING:
                default:
                    if (offsetInLine is 0) {
                        point = layout.getLocation(offsetInLine, false);
                    } else {
                        // SWT: Instead of go back one byte, go back one codepoint
                        int offsetInLine_m1 = layout.getPreviousOffset(offsetInLine, SWT.MOVEMENT_CLUSTER);
                        point = layout.getLocation(offsetInLine_m1, true);
                    }
                    break;
            }
        }
    } else {
        point = new Point(layout.getIndent(), 0);
    }
    renderer.disposeTextLayout(layout);
    point.x += leftMargin - horizontalScrollOffset;
    point.y += getLinePixel(lineIndex);
    return point;
}
/**
 * Inserts a string.  The old selection is replaced with the new text.
 *
 * @param string the string
 * @see #replaceTextRange(int,int,String)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void insert(String string) {
    checkWidget();
    // SWT extension: allow null for zero length string
//     if (string is null) {
//         SWT.error(SWT.ERROR_NULL_ARGUMENT);
//     }
    Point sel = getSelectionRange();
    replaceTextRange(sel.x, sel.y, string);
}
/**
 * Creates content change listeners and set the default content model.
 */
void installDefaultContent() {
    textChangeListener = new class() TextChangeListener {
        public void textChanging(TextChangingEvent event) {
            handleTextChanging(event);
        }
        public void textChanged(TextChangedEvent event) {
            handleTextChanged(event);
        }
        public void textSet(TextChangedEvent event) {
            handleTextSet(event);
        }
    };
    content = new DefaultContent();
    content.addTextChangeListener(textChangeListener);
}
/**
 * Adds event listeners
 */
void installListeners() {
    ScrollBar verticalBar = getVerticalBar();
    ScrollBar horizontalBar = getHorizontalBar();

    listener = new class() Listener {
        public void handleEvent(Event event) {
            switch (event.type) {
                case SWT.Dispose: handleDispose(event); break;
                case SWT.KeyDown: handleKeyDown(event); break;
                case SWT.KeyUp: handleKeyUp(event); break;
                case SWT.MouseDown: handleMouseDown(event); break;
                case SWT.MouseUp: handleMouseUp(event); break;
                case SWT.MouseMove: handleMouseMove(event); break;
                case SWT.Paint: handlePaint(event); break;
                case SWT.Resize: handleResize(event); break;
                case SWT.Traverse: handleTraverse(event); break;
                default:
            }
        }
    };
    addListener(SWT.Dispose, listener);
    addListener(SWT.KeyDown, listener);
    addListener(SWT.KeyUp, listener);
    addListener(SWT.MouseDown, listener);
    addListener(SWT.MouseUp, listener);
    addListener(SWT.MouseMove, listener);
    addListener(SWT.Paint, listener);
    addListener(SWT.Resize, listener);
    addListener(SWT.Traverse, listener);
    ime.addListener(SWT.ImeComposition, new class() Listener {
        public void handleEvent(Event event) {
            switch (event.detail) {
                case SWT.COMPOSITION_SELECTION: handleCompositionSelection(event); break;
                case SWT.COMPOSITION_CHANGED: handleCompositionChanged(event); break;
                case SWT.COMPOSITION_OFFSET: handleCompositionOffset(event); break;
                default:
            }
        }
    });
    if (verticalBar !is null) {
        verticalBar.addListener(SWT.Selection, new class() Listener {
            public void handleEvent(Event event) {
                handleVerticalScroll(event);
            }
        });
    }
    if (horizontalBar !is null) {
        horizontalBar.addListener(SWT.Selection, new class() Listener {
            public void handleEvent(Event event) {
                handleHorizontalScroll(event);
            }
        });
    }
}
void internalRedrawRange(int start, int length) {
    if (length <= 0) return;
    int end = start + length;
    int startLine = content.getLineAtOffset(start);
    int endLine = content.getLineAtOffset(end);
    int partialBottomIndex = getPartialBottomIndex();
    int partialTopIndex = getPartialTopIndex();
    if (startLine > partialBottomIndex || endLine < partialTopIndex) {
        return;
    }
    if (partialTopIndex > startLine) {
        startLine = partialTopIndex;
        start = 0;
    } else {
        start -= content.getOffsetAtLine(startLine);
    }
    if (partialBottomIndex < endLine) {
        endLine = partialBottomIndex + 1;
        end = 0;
    } else {
        end -= content.getOffsetAtLine(endLine);
    }

    TextLayout layout = renderer.getTextLayout(startLine);
    int lineX = leftMargin - horizontalScrollOffset, startLineY = getLinePixel(startLine);
    int[] offsets = layout.getLineOffsets();
    int startIndex = layout.getLineIndex(Math.min(start, layout.getText().length));

    /* Redraw end of line before start line if wrapped and start offset is first char */
    if (wordWrap && startIndex > 0 && offsets[startIndex] is start) {
        Rectangle rect = layout.getLineBounds(startIndex - 1);
        rect.x = rect.width;
        rect.width = clientAreaWidth - rightMargin - rect.x;
        rect.x += lineX;
        rect.y += startLineY;
        super.redraw(rect.x, rect.y, rect.width, rect.height, false);
    }

    if (startLine is endLine) {
        int endIndex = layout.getLineIndex(Math.min(end, layout.getText().length));
        if (startIndex is endIndex) {
            /* Redraw rect between start and end offset if start and end offsets are in same wrapped line */
            Rectangle rect = layout.getBounds(start, end - 1);
            rect.x += lineX;
            rect.y += startLineY;
            super.redraw(rect.x, rect.y, rect.width, rect.height, false);
            renderer.disposeTextLayout(layout);
            return;
        }
    }

    /* Redraw start line from the start offset to the end of client area */
    Rectangle startRect = layout.getBounds(start, offsets[startIndex + 1] - 1);
    if (startRect.height is 0) {
        Rectangle bounds = layout.getLineBounds(startIndex);
        startRect.x = bounds.width;
        startRect.y = bounds.y;
        startRect.height = bounds.height;
    }
    startRect.x += lineX;
    startRect.y += startLineY;
    startRect.width = clientAreaWidth - rightMargin - startRect.x;
    super.redraw(startRect.x, startRect.y, startRect.width, startRect.height, false);

    /* Redraw end line from the beginning of the line to the end offset */
    if (startLine !is endLine) {
        renderer.disposeTextLayout(layout);
        layout = renderer.getTextLayout(endLine);
        offsets = layout.getLineOffsets();
    }
    int endIndex = layout.getLineIndex(Math.min(end, layout.getText().length));
    Rectangle endRect = layout.getBounds(offsets[endIndex], end - 1);
    if (endRect.height is 0) {
        Rectangle bounds = layout.getLineBounds(endIndex);
        endRect.y = bounds.y;
        endRect.height = bounds.height;
    }
    endRect.x += lineX;
    endRect.y += getLinePixel(endLine);
    super.redraw(endRect.x, endRect.y, endRect.width, endRect.height, false);
    renderer.disposeTextLayout(layout);

    /* Redraw all lines in between start and end line */
    int y = startRect.y + startRect.height;
    if (endRect.y > y) {
        super.redraw(leftMargin, y, clientAreaWidth - rightMargin - leftMargin, endRect.y - y, false);
    }
}
void handleCompositionOffset (Event event) {
    int[] trailing = new int [1];
    event.index = getOffsetAtPoint(event.x, event.y, trailing, true);
    event.count = trailing[0];
}
void handleCompositionSelection (Event event) {
    event.start = selection.x;
    event.end = selection.y;
    event.text = getSelectionText();
}
void handleCompositionChanged(Event event) {
    String text = event.text;
    int start = event.start;
    int end = event.end;
    int length = text.length;
    if (length is ime.getCommitCount()) {
        content.replaceTextRange(start, end - start, "");
        caretOffset = ime.getCompositionOffset();
        caretWidth = 0;
        caretDirection = SWT.NULL;
    } else {
        content.replaceTextRange(start, end - start, text);
        caretOffset = ime.getCaretOffset();
        if (ime.getWideCaret()) {
            start = ime.getCompositionOffset();
            int lineIndex = getCaretLine();
            int lineOffset = content.getOffsetAtLine(lineIndex);
            TextLayout layout = renderer.getTextLayout(lineIndex);
            caretWidth = layout.getBounds(start - lineOffset, start + length - 1 - lineOffset).width;
            renderer.disposeTextLayout(layout);
        }
    }
    showCaret();
}
/**
 * Frees resources.
 */
void handleDispose(Event event) {
    removeListener(SWT.Dispose, listener);
    notifyListeners(SWT.Dispose, event);
    event.type = SWT.None;

    clipboard.dispose();
    if (renderer !is null) {
        renderer.dispose();
        renderer = null;
    }
    if (content !is null) {
        content.removeTextChangeListener(textChangeListener);
        content = null;
    }
    if (defaultCaret !is null) {
        defaultCaret.dispose();
        defaultCaret = null;
    }
    if (leftCaretBitmap !is null) {
        leftCaretBitmap.dispose();
        leftCaretBitmap = null;
    }
    if (rightCaretBitmap !is null) {
        rightCaretBitmap.dispose();
        rightCaretBitmap = null;
    }
    if (isBidiCaret()) {
        BidiUtil.removeLanguageListener(this);
    }
    selectionBackground = null;
    selectionForeground = null;
    textChangeListener = null;
    selection = null;
    doubleClickSelection = null;
    keyActionMap = null;
    background = null;
    foreground = null;
    clipboard = null;
}
/**
 * Scrolls the widget horizontally.
 */
void handleHorizontalScroll(Event event) {
    int scrollPixel = getHorizontalBar().getSelection() - horizontalScrollOffset;
    scrollHorizontal(scrollPixel, false);
}
/**
 * If an action has been registered for the key stroke execute the action.
 * Otherwise, if a character has been entered treat it as new content.
 *
 * @param event keyboard event
 */
void handleKey(Event event) {
    int action;
    caretAlignment = PREVIOUS_OFFSET_TRAILING;
    if (event.keyCode !is 0) {
        // special key pressed (e.g., F1)
        action = getKeyBinding(event.keyCode | event.stateMask);
    } else {
        // character key pressed
        action = getKeyBinding(event.character | event.stateMask);
        if (action is SWT.NULL) {
            // see if we have a control character
            if ((event.stateMask & SWT.CTRL) !is 0 && (event.character >= 0) && event.character <= 31) {
                // get the character from the CTRL+char sequence, the control
                // key subtracts 64 from the value of the key that it modifies
                int c = event.character + 64;
                action = getKeyBinding(c | event.stateMask);
            }
        }
    }
    if (action is SWT.NULL) {
        bool ignore = false;

        if (IS_CARBON) {
            // Ignore accelerator key combinations (we do not want to
            // insert a character in the text in this instance). Do not
            // ignore COMMAND+ALT combinations since that key sequence
            // produces characters on the mac.
            ignore = (event.stateMask ^ SWT.COMMAND) is 0 ||
                    (event.stateMask ^ (SWT.COMMAND | SWT.SHIFT)) is 0;
        } else if (IS_MOTIF) {
            // Ignore accelerator key combinations (we do not want to
            // insert a character in the text in this instance). Do not
            // ignore ALT combinations since this key sequence
            // produces characters on motif.
            ignore = (event.stateMask ^ SWT.CTRL) is 0 ||
                    (event.stateMask ^ (SWT.CTRL | SWT.SHIFT)) is 0;
        } else {
            // Ignore accelerator key combinations (we do not want to
            // insert a character in the text in this instance). Don't
            // ignore CTRL+ALT combinations since that is the Alt Gr
            // key on some keyboards.  See bug 20953.
            ignore = (event.stateMask ^ SWT.ALT) is 0 ||
                    (event.stateMask ^ SWT.CTRL) is 0 ||
                    (event.stateMask ^ (SWT.ALT | SWT.SHIFT)) is 0 ||
                    (event.stateMask ^ (SWT.CTRL | SWT.SHIFT)) is 0;
        }
        // -ignore anything below SPACE except for line delimiter keys and tab.
        // -ignore DEL
        if (!ignore && event.character > 31 && event.character !is SWT.DEL ||
            event.character is SWT.CR || event.character is SWT.LF ||
            event.character is TAB) {
            doContent(event.character);
            update();
        }
    } else {
        invokeAction(action);
    }
}
/**
 * If a VerifyKey listener exists, verify that the key that was entered
 * should be processed.
 *
 * @param event keyboard event
 */
void handleKeyDown(Event event) {
    if (clipboardSelection is null) {
        clipboardSelection = new Point(selection.x, selection.y);
    }

    Event verifyEvent = new Event();
    verifyEvent.character = event.character;
    verifyEvent.keyCode = event.keyCode;
    verifyEvent.stateMask = event.stateMask;
    verifyEvent.doit = true;
    notifyListeners(VerifyKey, verifyEvent);
    if (verifyEvent.doit) {
        handleKey(event);
    }
}
/**
 * Update the Selection Clipboard.
 *
 * @param event keyboard event
 */
void handleKeyUp(Event event) {
    if (clipboardSelection !is null) {
        if (clipboardSelection.x !is selection.x || clipboardSelection.y !is selection.y) {
            try {
                if (selection.y - selection.x > 0) {
                    setClipboardContent(selection.x, selection.y - selection.x, DND.SELECTION_CLIPBOARD);
                }
            } catch (SWTError error) {
                // Copy to clipboard failed. This happens when another application
                // is accessing the clipboard while we copy. Ignore the error.
                // Fixes 1GDQAVN
                // Rethrow all other errors. Fixes bug 17578.
                if (error.code !is DND.ERROR_CANNOT_SET_CLIPBOARD) {
                    throw error;
                }
            }
        }
    }
    clipboardSelection = null;
}
/**
 * Updates the caret location and selection if mouse button 1 has been
 * pressed.
 */
void handleMouseDown(Event event) {
    //force focus (object support)
    forceFocus();

    //drag detect
    if (dragDetect_ && checkDragDetect(event)) return;

    //paste clipboard selection
    if (event.button is 2) {
        String text = stringcast(getClipboardContent(DND.SELECTION_CLIPBOARD));
        if (text !is null && text.length > 0) {
            // position cursor
            doMouseLocationChange(event.x, event.y, false);
            // insert text
            Event e = new Event();
            e.start = selection.x;
            e.end = selection.y;
            e.text = getModelDelimitedText(text);
            sendKeyEvent(e);
        }
    }

    //set selection
    if ((event.button !is 1) || (IS_CARBON && (event.stateMask & SWT.MOD4) !is 0)) {
        return;
    }
    clickCount = event.count;
    if (clickCount is 1) {
        bool select = (event.stateMask & SWT.MOD2) !is 0;
        doMouseLocationChange(event.x, event.y, select);
    } else {
        if (doubleClickEnabled) {
            clearSelection(false);
            int offset = getOffsetAtPoint(event.x, event.y);
            int lineIndex = content.getLineAtOffset(offset);
            int lineOffset = content.getOffsetAtLine(lineIndex);
            int lineEnd = content.getCharCount();
            if (lineIndex + 1 < content.getLineCount()) {
                lineEnd = content.getOffsetAtLine(lineIndex + 1);
            }
            int start, end;
            if ((clickCount & 1) is 0) {
                start = Math.max(0, getWordPrevious(offset, SWT.MOVEMENT_WORD_START));
                end = Math.min(content.getCharCount(), getWordNext(start, SWT.MOVEMENT_WORD_END));
            } else {
                start = lineOffset;
                end = lineEnd;
            }
            caretOffset = start;
            resetSelection();
            caretOffset = end;
            showCaret();
            doMouseSelection();
            doubleClickSelection = new Point(selection.x, selection.y);
        }
    }
}
/**
 * Updates the caret location and selection if mouse button 1 is pressed
 * during the mouse move.
 */
void handleMouseMove(Event event) {
    if (clickCount is 0) return;
    doMouseLocationChange(event.x, event.y, true);
    update();
    doAutoScroll(event);
}
/**
 * Autoscrolling ends when the mouse button is released.
 */
void handleMouseUp(Event event) {
    clickCount = 0;
    endAutoScroll();
    if (event.button is 1) {
        try {
            if (selection.y - selection.x > 0) {
                setClipboardContent(selection.x, selection.y - selection.x, DND.SELECTION_CLIPBOARD);
            }
        } catch (SWTError error) {
            // Copy to clipboard failed. This happens when another application
            // is accessing the clipboard while we copy. Ignore the error.
            // Fixes 1GDQAVN
            // Rethrow all other errors. Fixes bug 17578.
            if (error.code !is DND.ERROR_CANNOT_SET_CLIPBOARD) {
                throw error;
            }
        }
    }
}
/**
 * Renders the invalidated area specified in the paint event.
 *
 * @param event paint event
 */
void handlePaint(Event event) {
    if (event.width is 0 || event.height is 0) return;
    if (clientAreaWidth is 0 || clientAreaHeight is 0) return;

    int startLine = getLineIndex(event.y);
    int y = getLinePixel(startLine);
    int endY = event.y + event.height;
    GC gc = event.gc;
    Color background = getBackground();
    Color foreground = getForeground();
    if (endY > 0) {
        int lineCount = isSingleLine() ? 1 : content.getLineCount();
        int x = leftMargin - horizontalScrollOffset;
        for (int i = startLine; y < endY && i < lineCount; i++) {
            y += renderer.drawLine(i, x, y, gc, background, foreground);
        }
        if (y < endY) {
            gc.setBackground(background);
            drawBackground(gc, 0, y, clientAreaWidth, endY - y);
        }
    }
    // fill the margin background
    gc.setBackground(background);
    if (topMargin > 0) {
        drawBackground(gc, 0, 0, clientAreaWidth, topMargin);
    }
    if (bottomMargin > 0) {
        drawBackground(gc, 0, clientAreaHeight - bottomMargin, clientAreaWidth, bottomMargin);
    }
    if (leftMargin > 0) {
        drawBackground(gc, 0, 0, leftMargin, clientAreaHeight);
    }
    if (rightMargin > 0) {
        drawBackground(gc, clientAreaWidth - rightMargin, 0, rightMargin, clientAreaHeight);
    }
}
/**
 * Recalculates the scroll bars. Rewraps all lines when in word
 * wrap mode.
 *
 * @param event resize event
 */
void handleResize(Event event) {
    int oldHeight = clientAreaHeight;
    int oldWidth = clientAreaWidth;
    Rectangle clientArea = getClientArea();
    clientAreaHeight = clientArea.height;
    clientAreaWidth = clientArea.width;
    /* Redraw the old or new right/bottom margin if needed */
    if (oldWidth !is clientAreaWidth) {
        if (rightMargin > 0) {
            int x = (oldWidth < clientAreaWidth ? oldWidth : clientAreaWidth) - rightMargin;
            super.redraw(x, 0, rightMargin, oldHeight, false);
        }
    }
    if (oldHeight !is clientAreaHeight) {
        if (bottomMargin > 0) {
            int y = (oldHeight < clientAreaHeight ? oldHeight : clientAreaHeight) - bottomMargin;
            super.redraw(0, y, oldWidth, bottomMargin, false);
        }
    }
    if (wordWrap) {
        if (oldWidth !is clientAreaWidth) {
            renderer.reset(0, content.getLineCount());
            verticalScrollOffset = -1;
            renderer.calculateIdle();
            super.redraw();
        }
        if (oldHeight !is clientAreaHeight) {
            if (oldHeight is 0) topIndexY = 0;
            setScrollBars(true);
        }
        setCaretLocation();
    } else  {
        renderer.calculateClientArea();
        setScrollBars(true);
        claimRightFreeSpace();
        // StyledText allows any value for horizontalScrollOffset when clientArea is zero
        // in setHorizontalPixel() and setHorisontalOffset(). Fixes bug 168429.
        if (clientAreaWidth !is 0) {
            ScrollBar horizontalBar = getHorizontalBar();
            if (horizontalBar !is null && horizontalBar.getVisible()) {
                if (horizontalScrollOffset !is horizontalBar.getSelection()) {
                    horizontalBar.setSelection(horizontalScrollOffset);
                    horizontalScrollOffset = horizontalBar.getSelection();
                }
            }
        }
    }
    claimBottomFreeSpace();
    //TODO FIX TOP INDEX DURING RESIZE
//  if (oldHeight !is clientAreaHeight || wordWrap) {
//      calculateTopIndex(0);
//  }
}
/**
 * Updates the caret position and selection and the scroll bars to reflect
 * the content change.
 */
void handleTextChanged(TextChangedEvent event) {
    int offset = ime.getCompositionOffset();
    if (offset !is -1 && lastTextChangeStart < offset) {
        ime.setCompositionOffset(offset + lastTextChangeNewCharCount - lastTextChangeReplaceCharCount);
    }
    int firstLine = content.getLineAtOffset(lastTextChangeStart);
    resetCache(firstLine, 0);
    if (!isFixedLineHeight() && topIndex > firstLine) {
        topIndex = firstLine;
        topIndexY = 0;
        super.redraw();
    } else {
        int lastLine = firstLine + lastTextChangeNewLineCount;
        int firstLineTop = getLinePixel(firstLine);
        int newLastLineBottom = getLinePixel(lastLine + 1);
        if (lastLineBottom !is newLastLineBottom) {
            super.redraw();
        } else {
            super.redraw(0, firstLineTop, clientAreaWidth, newLastLineBottom - firstLineTop, false);
            redrawLinesBullet(renderer.redrawLines);
        }
    }
    renderer.redrawLines = null;
    // update selection/caret location after styles have been changed.
    // otherwise any text measuring could be incorrect
    //
    // also, this needs to be done after all scrolling. Otherwise,
    // selection redraw would be flushed during scroll which is wrong.
    // in some cases new text would be drawn in scroll source area even
    // though the intent is to scroll it.
    updateSelection(lastTextChangeStart, lastTextChangeReplaceCharCount, lastTextChangeNewCharCount);
    if (lastTextChangeReplaceLineCount > 0 || wordWrap) {
        claimBottomFreeSpace();
    }
    if (lastTextChangeReplaceCharCount > 0) {
        claimRightFreeSpace();
    }
}
/**
 * Updates the screen to reflect a pending content change.
 *
 * @param event .start the start offset of the change
 * @param event .newText text that is going to be inserted or empty String
 *  if no text will be inserted
 * @param event .replaceCharCount length of text that is going to be replaced
 * @param event .newCharCount length of text that is going to be inserted
 * @param event .replaceLineCount number of lines that are going to be replaced
 * @param event .newLineCount number of new lines that are going to be inserted
 */
void handleTextChanging(TextChangingEvent event) {
    if (event.replaceCharCount < 0) {
        event.start += event.replaceCharCount;
        event.replaceCharCount *= -1;
    }
    lastTextChangeStart = event.start;
    lastTextChangeNewLineCount = event.newLineCount;
    lastTextChangeNewCharCount = event.newCharCount;
    lastTextChangeReplaceLineCount = event.replaceLineCount;
    lastTextChangeReplaceCharCount = event.replaceCharCount;
    int lineIndex = content.getLineAtOffset(event.start);
    int srcY = getLinePixel(lineIndex + event.replaceLineCount + 1);
    int destY = getLinePixel(lineIndex + 1) + event.newLineCount * renderer.getLineHeight();
    lastLineBottom = destY;
    if (srcY < 0 && destY < 0) {
        lastLineBottom += srcY - destY;
        verticalScrollOffset += destY - srcY;
        calculateTopIndex(destY - srcY);
        setScrollBars(true);
    } else {
        scrollText(srcY, destY);
    }

    renderer.textChanging(event);

    // Update the caret offset if it is greater than the length of the content.
    // This is necessary since style range API may be called between the
    // handleTextChanging and handleTextChanged events and this API sets the
    // caretOffset.
    int newEndOfText = content.getCharCount() - event.replaceCharCount + event.newCharCount;
    if (caretOffset > newEndOfText) caretOffset = newEndOfText;
}
/**
 * Called when the widget content is set programmatically, overwriting
 * the old content. Resets the caret position, selection and scroll offsets.
 * Recalculates the content width and scroll bars. Redraws the widget.
 *
 * @param event text change event.
 */
void handleTextSet(TextChangedEvent event) {
    reset();
}
/**
 * Called when a traversal key is pressed.
 * Allow tab next traversal to occur when the widget is in single
 * line mode or in multi line and non-editable mode .
 * When in editable multi line mode we want to prevent the tab
 * traversal and receive the tab key event instead.
 *
 * @param event the event
 */
void handleTraverse(Event event) {
    switch (event.detail) {
        case SWT.TRAVERSE_ESCAPE:
        case SWT.TRAVERSE_PAGE_NEXT:
        case SWT.TRAVERSE_PAGE_PREVIOUS:
            event.doit = true;
            break;
        case SWT.TRAVERSE_RETURN:
        case SWT.TRAVERSE_TAB_NEXT:
        case SWT.TRAVERSE_TAB_PREVIOUS:
            if ((getStyle() & SWT.SINGLE) !is 0) {
                event.doit = true;
            } else {
                if (!editable || (event.stateMask & SWT.MODIFIER_MASK) !is 0) {
                    event.doit = true;
                }
            }
            break;
        default:
    }
}
/**
 * Scrolls the widget vertically.
 */
void handleVerticalScroll(Event event) {
    int scrollPixel = getVerticalBar().getSelection() - getVerticalScrollOffset();
    scrollVertical(scrollPixel, false);
}
/**
 * Add accessibility support for the widget.
 */
void initializeAccessible() {
    Accessible accessible = getAccessible();
    accessible.addAccessibleListener(new class() AccessibleAdapter {
        public void getName (AccessibleEvent e) {
            String name = null;
            Label label = getAssociatedLabel ();
            if (label !is null) {
                name = stripMnemonic (label.getText());
            }
            e.result = name;
        }
        public void getHelp(AccessibleEvent e) {
            e.result = getToolTipText();
        }
        public void getKeyboardShortcut(AccessibleEvent e) {
            String shortcut = null;
            Label label = getAssociatedLabel ();
            if (label !is null) {
                String text = label.getText ();
                if (text !is null) {
                    dchar mnemonic = _findMnemonic (text);
                    if (mnemonic !is '\0') {
                        shortcut = "Alt+"~dcharToString(mnemonic); //$NON-NLS-1$
                    }
                }
            }
            e.result = shortcut;
        }
    });
    accessible.addAccessibleTextListener(new class() AccessibleTextAdapter {
        public void getCaretOffset(AccessibleTextEvent e) {
            e.offset = this.outer.getCaretOffset();
        }
        public void getSelectionRange(AccessibleTextEvent e) {
            Point selection = this.outer.getSelectionRange();
            e.offset = selection.x;
            e.length = selection.y;
        }
    });
    accessible.addAccessibleControlListener(new class() AccessibleControlAdapter {
        public void getRole(AccessibleControlEvent e) {
            e.detail = ACC.ROLE_TEXT;
        }
        public void getState(AccessibleControlEvent e) {
            int state = 0;
            if (isEnabled()) state |= ACC.STATE_FOCUSABLE;
            if (isFocusControl()) state |= ACC.STATE_FOCUSED;
            if (!isVisible()) state |= ACC.STATE_INVISIBLE;
            if (!getEditable()) state |= ACC.STATE_READONLY;
            e.detail = state;
        }
        public void getValue(AccessibleControlEvent e) {
            e.result = this.outer.getText();
        }
    });
    addListener(SWT.FocusIn, new class(accessible) Listener {
        Accessible acc;
        this( Accessible acc ){ this.acc = acc; }
        public void handleEvent(Event event) {
            acc.setFocus(ACC.CHILDID_SELF);
        }
    });
}
/*
 * Return the Label immediately preceding the receiver in the z-order,
 * or null if none.
 */
Label getAssociatedLabel () {
    Control[] siblings = getParent ().getChildren ();
    for (int i = 0; i < siblings.length; i++) {
        if (siblings [i] is this) {
            if (i > 0 && ( null !is cast(Label)siblings [i-1])) {
                return cast(Label) siblings [i-1];
            }
        }
    }
    return null;
}
String stripMnemonic (String string) {
    int index = 0;
    int length_ = string.length;
    do {
        while ((index < length_) && (string[index] !is '&')) index++;
        if (++index >= length_) return string;
        if (string[index] !is '&') {
            return string.substring(0, index-1) ~ string.substring(index, length_);
        }
        index++;
    } while (index < length_);
    return string;
}
/*
 * Return the lowercase of the first non-'&' character following
 * an '&' character in the given string. If there are no '&'
 * characters in the given string, return '\0'.
 */
dchar _findMnemonic (String string) {
    if (string is null) return '\0';
    int index = 0;
    int length_ = string.length;
    do {
        while (index < length_ && string[index] !is '&') index++;
        if (++index >= length_) return '\0';
        if (string[index] !is '&') return CharacterFirstToLower(string[index .. $ ] );
        index++;
    } while (index < length_);
    return '\0';
}
/**
 * Executes the action.
 *
 * @param action one of the actions defined in ST.java
 */
public void invokeAction(int action) {
    checkWidget();
    updateCaretDirection = true;
    switch (action) {
        // Navigation
        case ST.LINE_UP:
            doLineUp(false);
            clearSelection(true);
            break;
        case ST.LINE_DOWN:
            doLineDown(false);
            clearSelection(true);
            break;
        case ST.LINE_START:
            doLineStart();
            clearSelection(true);
            break;
        case ST.LINE_END:
            doLineEnd();
            clearSelection(true);
            break;
        case ST.COLUMN_PREVIOUS:
            doCursorPrevious();
            clearSelection(true);
            break;
        case ST.COLUMN_NEXT:
            doCursorNext();
            clearSelection(true);
            break;
        case ST.PAGE_UP:
            doPageUp(false, -1);
            clearSelection(true);
            break;
        case ST.PAGE_DOWN:
            doPageDown(false, -1);
            clearSelection(true);
            break;
        case ST.WORD_PREVIOUS:
            doWordPrevious();
            clearSelection(true);
            break;
        case ST.WORD_NEXT:
            doWordNext();
            clearSelection(true);
            break;
        case ST.TEXT_START:
            doContentStart();
            clearSelection(true);
            break;
        case ST.TEXT_END:
            doContentEnd();
            clearSelection(true);
            break;
        case ST.WINDOW_START:
            doPageStart();
            clearSelection(true);
            break;
        case ST.WINDOW_END:
            doPageEnd();
            clearSelection(true);
            break;
        // Selection
        case ST.SELECT_LINE_UP:
            doSelectionLineUp();
            break;
        case ST.SELECT_ALL:
            selectAll();
            break;
        case ST.SELECT_LINE_DOWN:
            doSelectionLineDown();
            break;
        case ST.SELECT_LINE_START:
            doLineStart();
            doSelection(ST.COLUMN_PREVIOUS);
            break;
        case ST.SELECT_LINE_END:
            doLineEnd();
            doSelection(ST.COLUMN_NEXT);
            break;
        case ST.SELECT_COLUMN_PREVIOUS:
            doSelectionCursorPrevious();
            doSelection(ST.COLUMN_PREVIOUS);
            break;
        case ST.SELECT_COLUMN_NEXT:
            doSelectionCursorNext();
            doSelection(ST.COLUMN_NEXT);
            break;
        case ST.SELECT_PAGE_UP:
            doSelectionPageUp(-1);
            break;
        case ST.SELECT_PAGE_DOWN:
            doSelectionPageDown(-1);
            break;
        case ST.SELECT_WORD_PREVIOUS:
            doSelectionWordPrevious();
            doSelection(ST.COLUMN_PREVIOUS);
            break;
        case ST.SELECT_WORD_NEXT:
            doSelectionWordNext();
            doSelection(ST.COLUMN_NEXT);
            break;
        case ST.SELECT_TEXT_START:
            doContentStart();
            doSelection(ST.COLUMN_PREVIOUS);
            break;
        case ST.SELECT_TEXT_END:
            doContentEnd();
            doSelection(ST.COLUMN_NEXT);
            break;
        case ST.SELECT_WINDOW_START:
            doPageStart();
            doSelection(ST.COLUMN_PREVIOUS);
            break;
        case ST.SELECT_WINDOW_END:
            doPageEnd();
            doSelection(ST.COLUMN_NEXT);
            break;
        // Modification
        case ST.CUT:
            cut();
            break;
        case ST.COPY:
            copy();
            break;
        case ST.PASTE:
            paste();
            break;
        case ST.DELETE_PREVIOUS:
            doBackspace();
            break;
        case ST.DELETE_NEXT:
            doDelete();
            break;
        case ST.DELETE_WORD_PREVIOUS:
            doDeleteWordPrevious();
            break;
        case ST.DELETE_WORD_NEXT:
            doDeleteWordNext();
            break;
        // Miscellaneous
        case ST.TOGGLE_OVERWRITE:
            overwrite = !overwrite;     // toggle insert/overwrite mode
            break;
        default:
    }
}
/**
 * Temporary until SWT provides this
 */
bool isBidi() {
    return IS_GTK || IS_CARBON || BidiUtil.isBidiPlatform() || isMirrored_;
}
bool isBidiCaret() {
    return BidiUtil.isBidiPlatform();
}
bool isFixedLineHeight() {
    return fixedLineHeight;
}
/**
 * Returns whether the given offset is inside a multi byte line delimiter.
 * Example:
 * "Line1\r\n" isLineDelimiter(5) is false but isLineDelimiter(6) is true
 *
 * @return true if the given offset is inside a multi byte line delimiter.
 * false if the given offset is before or after a line delimiter.
 */
bool isLineDelimiter(int offset) {
    int line = content.getLineAtOffset(offset);
    int lineOffset = content.getOffsetAtLine(line);
    int offsetInLine = offset - lineOffset;
    // offsetInLine will be greater than line length if the line
    // delimiter is longer than one character and the offset is set
    // in between parts of the line delimiter.
    return offsetInLine > content.getLine(line).length;
}
/**
 * Returns whether the widget is mirrored (right oriented/right to left
 * writing order).
 *
 * @return isMirrored true=the widget is right oriented, false=the widget
 *  is left oriented
 */
bool isMirrored() {
    return isMirrored_;
}
/**
 * Returns whether the widget can have only one line.
 *
 * @return true if widget can have only one line, false if widget can have
 *  multiple lines
 */
bool isSingleLine() {
    return (getStyle() & SWT.SINGLE) !is 0;
}
/**
 * Sends the specified verify event, replace/insert text as defined by
 * the event and send a modify event.
 *
 * @param event the text change event.
 *  <ul>
 *  <li>event.start - the replace start offset</li>
 *  <li>event.end - the replace end offset</li>
 *  <li>event.text - the new text</li>
 *  </ul>
 * @param updateCaret whether or not he caret should be set behind
 *  the new text
 */
void modifyContent(Event event, bool updateCaret) {
    event.doit = true;
    notifyListeners(SWT.Verify, event);
    if (event.doit) {
        StyledTextEvent styledTextEvent = null;
        int replacedLength = event.end - event.start;
        if (isListening(ExtendedModify)) {
            styledTextEvent = new StyledTextEvent(content);
            styledTextEvent.start = event.start;
            styledTextEvent.end = event.start + event.text.length;
            styledTextEvent.text = content.getTextRange(event.start, replacedLength);
        }
        if (updateCaret) {
            //Fix advancing flag for delete/backspace key on direction boundary
            if (event.text.length is 0) {
                int lineIndex = content.getLineAtOffset(event.start);
                int lineOffset = content.getOffsetAtLine(lineIndex);
                TextLayout layout = renderer.getTextLayout(lineIndex);
                int levelStart = layout.getLevel(event.start - lineOffset);
                int lineIndexEnd = content.getLineAtOffset(event.end);
                if (lineIndex !is lineIndexEnd) {
                    renderer.disposeTextLayout(layout);
                    lineOffset = content.getOffsetAtLine(lineIndexEnd);
                    layout = renderer.getTextLayout(lineIndexEnd);
                }
                int levelEnd = layout.getLevel(event.end - lineOffset);
                renderer.disposeTextLayout(layout);
                if (levelStart !is levelEnd) {
                    caretAlignment = PREVIOUS_OFFSET_TRAILING;
                } else {
                    caretAlignment = OFFSET_LEADING;
                }
            }
        }
        content.replaceTextRange(event.start, replacedLength, event.text);
        // set the caret position prior to sending the modify event.
        // fixes 1GBB8NJ
        if (updateCaret) {
            // always update the caret location. fixes 1G8FODP
            setSelection(event.start + event.text.length, 0, true);
            showCaret();
        }
        sendModifyEvent(event);
        if (isListening(ExtendedModify)) {
            notifyListeners(ExtendedModify, styledTextEvent);
        }
    }
}
void paintObject(GC gc, int x, int y, int ascent, int descent, StyleRange style, Bullet bullet, int bulletIndex) {
    if (isListening(PaintObject)) {
        StyledTextEvent event = new StyledTextEvent (content) ;
        event.gc = gc;
        event.x = x;
        event.y = y;
        event.ascent = ascent;
        event.descent = descent;
        event.style = style;
        event.bullet = bullet;
        event.bulletIndex = bulletIndex;
        notifyListeners(PaintObject, event);
    }
}
/**
 * Replaces the selection with the text on the <code>DND.CLIPBOARD</code>
 * clipboard  or, if there is no selection,  inserts the text at the current
 * caret offset.   If the widget has the SWT.SINGLE style and the
 * clipboard text contains more than one line, only the first line without
 * line delimiters is  inserted in the widget.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void paste(){
    checkWidget();
    String text = stringcast( getClipboardContent(DND.CLIPBOARD));
    if (text !is null && text.length > 0) {
        Event event = new Event();
        event.start = selection.x;
        event.end = selection.y;
        event.text = getModelDelimitedText(text);
        sendKeyEvent(event);
    }
}
/**
 * Prints the widget's text to the default printer.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void print() {
    checkWidget();
    Printer printer = new Printer();
    StyledTextPrintOptions options = new StyledTextPrintOptions();
    options.printTextForeground = true;
    options.printTextBackground = true;
    options.printTextFontStyle = true;
    options.printLineBackground = true;
    (new Printing(this, printer, options)).run();
    printer.dispose();
}
/**
 * Returns a runnable that will print the widget's text
 * to the specified printer.
 * <p>
 * The runnable may be run in a non-UI thread.
 * </p>
 *
 * @param printer the printer to print to
 *
 * @return a <code>Runnable</code> for printing the receiver's text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when printer is null</li>
 * </ul>
 */
public Runnable print(Printer printer) {
    checkWidget();
    if (printer is null) {
        SWT.error(SWT.ERROR_NULL_ARGUMENT);
    }
    StyledTextPrintOptions options = new StyledTextPrintOptions();
    options.printTextForeground = true;
    options.printTextBackground = true;
    options.printTextFontStyle = true;
    options.printLineBackground = true;
    return print(printer, options);
}
/**
 * Returns a runnable that will print the widget's text
 * to the specified printer.
 * <p>
 * The runnable may be run in a non-UI thread.
 * </p>
 *
 * @param printer the printer to print to
 * @param options print options to use during printing
 *
 * @return a <code>Runnable</code> for printing the receiver's text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when printer or options is null</li>
 * </ul>
 * @since 2.1
 */
public Runnable print(Printer printer, StyledTextPrintOptions options) {
    checkWidget();
    if (printer is null || options is null) {
        SWT.error(SWT.ERROR_NULL_ARGUMENT);
    }
    return new Printing(this, printer, options);
}
/**
 * Causes the entire bounds of the receiver to be marked
 * as needing to be redrawn. The next time a paint request
 * is processed, the control will be completely painted.
 * <p>
 * Recalculates the content width for all lines in the bounds.
 * When a <code>LineStyleListener</code> is used a redraw call
 * is the only notification to the widget that styles have changed
 * and that the content width may have changed.
 * </p>
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see Control#update()
 */
public override void redraw() {
    super.redraw();
    int itemCount = getPartialBottomIndex() - topIndex + 1;
    renderer.reset(topIndex, itemCount);
    renderer.calculate(topIndex, itemCount);
    setScrollBars(false);
}
/**
 * Causes the rectangular area of the receiver specified by
 * the arguments to be marked as needing to be redrawn.
 * The next time a paint request is processed, that area of
 * the receiver will be painted. If the <code>all</code> flag
 * is <code>true</code>, any children of the receiver which
 * intersect with the specified area will also paint their
 * intersecting areas. If the <code>all</code> flag is
 * <code>false</code>, the children will not be painted.
 * <p>
 * Marks the content width of all lines in the specified rectangle
 * as unknown. Recalculates the content width of all visible lines.
 * When a <code>LineStyleListener</code> is used a redraw call
 * is the only notification to the widget that styles have changed
 * and that the content width may have changed.
 * </p>
 *
 * @param x the x coordinate of the area to draw
 * @param y the y coordinate of the area to draw
 * @param width the width of the area to draw
 * @param height the height of the area to draw
 * @param all <code>true</code> if children should redraw, and <code>false</code> otherwise
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see Control#update()
 */
public override void redraw(int x, int y, int width, int height, bool all) {
    super.redraw(x, y, width, height, all);
    if (height > 0) {
        int firstLine = getLineIndex(y);
        int lastLine = getLineIndex(y + height);
        resetCache(firstLine, lastLine - firstLine + 1);
    }
}
void redrawLines(int startLine, int lineCount) {
    // do nothing if redraw range is completely invisible
    int partialBottomIndex = getPartialBottomIndex();
    if (startLine > partialBottomIndex || startLine + lineCount - 1 < topIndex) {
        return;
    }
    // only redraw visible lines
    if (startLine < topIndex) {
        lineCount -= topIndex - startLine;
        startLine = topIndex;
    }
    if (startLine + lineCount - 1 > partialBottomIndex) {
        lineCount = partialBottomIndex - startLine + 1;
    }
    startLine -= topIndex;
    int redrawTop = getLinePixel(startLine);
    int redrawBottom = getLinePixel(startLine + lineCount);
    int redrawWidth = clientAreaWidth - leftMargin - rightMargin;
    super.redraw(leftMargin, redrawTop, redrawWidth, redrawBottom - redrawTop, true);
}
void redrawLinesBullet (int[] redrawLines) {
    if (redrawLines is null) return;
    int topIndex = getPartialTopIndex();
    int bottomIndex = getPartialBottomIndex();
    for (int i = 0; i < redrawLines.length; i++) {
        int lineIndex = redrawLines[i];
        if (!(topIndex <= lineIndex && lineIndex <= bottomIndex)) continue;
        int width = -1;
        Bullet bullet = renderer.getLineBullet(lineIndex, null);
        if (bullet !is null) {
            StyleRange style = bullet.style;
            GlyphMetrics metrics = style.metrics;
            width = metrics.width;
        }
        if (width is -1) width = getClientArea().width;
        int height = renderer.getLineHeight(lineIndex);
        int y = getLinePixel(lineIndex);
        super.redraw(0, y, width, height, false);
    }
}
/**
 * Redraws the specified text range.
 *
 * @param start offset of the first character to redraw
 * @param length number of characters to redraw
 * @param clearBackground true if the background should be cleared as
 *  part of the redraw operation.  If true, the entire redraw range will
 *  be cleared before anything is redrawn.  If the redraw range includes
 *  the last character of a line (i.e., the entire line is redrawn) the
 *  line is cleared all the way to the right border of the widget.
 *  The redraw operation will be faster and smoother if clearBackground
 *  is set to false.  Whether or not the flag can be set to false depends
 *  on the type of change that has taken place.  If font styles or
 *  background colors for the redraw range have changed, clearBackground
 *  should be set to true.  If only foreground colors have changed for
 *  the redraw range, clearBackground can be set to false.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when start and/or end are outside the widget content</li>
 * </ul>
 */
public void redrawRange(int start, int length, bool clearBackground) {
    checkWidget();
    int end = start + length;
    int contentLength = content.getCharCount();
    if (start > end || start < 0 || end > contentLength) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    int firstLine = content.getLineAtOffset(start);
    int lastLine = content.getLineAtOffset(end);
    resetCache(firstLine, lastLine - firstLine + 1);
    internalRedrawRange(start, length);
}
/**
 * Removes the specified bidirectional segment listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 *
 * @since 2.0
 */
public void removeBidiSegmentListener(BidiSegmentListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(LineGetSegments, listener);
}
/**
 * Removes the specified extended modify listener.
 *
 * @param extendedModifyListener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeExtendedModifyListener(ExtendedModifyListener extendedModifyListener) {
    checkWidget();
    if (extendedModifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(ExtendedModify, extendedModifyListener);
}
/**
 * Removes the specified line background listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeLineBackgroundListener(LineBackgroundListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(LineGetBackground, listener);
}
/**
 * Removes the specified line style listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeLineStyleListener(LineStyleListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(LineGetStyle, listener);
}
/**
 * Removes the specified modify listener.
 *
 * @param modifyListener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeModifyListener(ModifyListener modifyListener) {
    checkWidget();
    if (modifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(SWT.Modify, modifyListener);
}
/**
 * Removes the specified listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 * @since 3.2
 */
public void removePaintObjectListener(PaintObjectListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(PaintObject, listener);
}
/**
 * Removes the listener from the collection of listeners who will
 * be notified when the user changes the receiver's selection.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener(SelectionListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(SWT.Selection, listener);
}
/**
 * Removes the specified verify listener.
 *
 * @param verifyListener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeVerifyListener(VerifyListener verifyListener) {
    checkWidget();
    if (verifyListener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(SWT.Verify, verifyListener);
}
/**
 * Removes the specified key verify listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void removeVerifyKeyListener(VerifyKeyListener listener) {
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(VerifyKey, listener);
}
/**
 * Removes the specified word movement listener.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 *
 * @see MovementEvent
 * @see MovementListener
 * @see #addWordMovementListener
 *
 * @since 3.3
 */

public void removeWordMovementListener(MovementListener listener) {
    checkWidget();
    if (listener is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    removeListener(WordNext, listener);
    removeListener(WordPrevious, listener);
}
/**
 * Replaces the styles in the given range with new styles.  This method
 * effectively deletes the styles in the given range and then adds the
 * the new styles.
 * <p>
 * Note: Because a StyleRange includes the start and length, the
 * same instance cannot occur multiple times in the array of styles.
 * If the same style attributes, such as font and color, occur in
 * multiple StyleRanges, <code>setStyleRanges(int, int, int[], StyleRange[])</code>
 * can be used to share styles and reduce memory usage.
 * </p><p>
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param start offset of first character where styles will be deleted
 * @param length length of the range to delete styles in
 * @param ranges StyleRange objects containing the new style information.
 * The ranges should not overlap and should be within the specified start
 * and length. The style rendering is undefined if the ranges do overlap
 * or are ill-defined. Must not be null.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when either start or end is outside the valid range (0 <= offset <= getCharCount())</li>
 * </ul>
 *
 * @since 2.0
 *
 * @see #setStyleRanges(int, int, int[], StyleRange[])
 */
public void replaceStyleRanges(int start, int length, StyleRange[] ranges) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    // SWT extension: allow null for zero length string
    //if (ranges is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    setStyleRanges(start, length, null, ranges, false);
}
/**
 * Replaces the given text range with new text.
 * If the widget has the SWT.SINGLE style and "text" contains more than
 * one line, only the first line is rendered but the text is stored
 * unchanged. A subsequent call to getText will return the same text
 * that was set. Note that only a single line of text should be set when
 * the SWT.SINGLE style is used.
 * <p>
 * <b>NOTE:</b> During the replace operation the current selection is
 * changed as follows:
 * <ul>
 * <li>selection before replaced text: selection unchanged
 * <li>selection after replaced text: adjust the selection so that same text
 * remains selected
 * <li>selection intersects replaced text: selection is cleared and caret
 * is placed after inserted text
 * </ul>
 * </p>
 *
 * @param start offset of first character to replace
 * @param length number of characters to replace. Use 0 to insert text
 * @param text new text. May be empty to delete text.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when either start or end is outside the valid range (0 <= offset <= getCharCount())</li>
 *   <li>ERROR_INVALID_ARGUMENT when either start or end is inside a multi byte line delimiter.
 *      Splitting a line delimiter for example by inserting text in between the CR and LF and deleting part of a line delimiter is not supported</li>
 * </ul>
 */
public void replaceTextRange(int start, int length, String text) {
    checkWidget();
    // SWT extension: allow null for zero length string
//     if (text is null) {
//         SWT.error(SWT.ERROR_NULL_ARGUMENT);
//     }
    int contentLength = getCharCount();
    int end = start + length;
    if (start > end || start < 0 || end > contentLength) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    Event event = new Event();
    event.start = start;
    event.end = end;
    event.text = text;
    modifyContent(event, false);
}
/**
 * Resets the caret position, selection and scroll offsets. Recalculate
 * the content width and scroll bars. Redraw the widget.
 */
void reset() {
    ScrollBar verticalBar = getVerticalBar();
    ScrollBar horizontalBar = getHorizontalBar();
    caretOffset = 0;
    topIndex = 0;
    topIndexY = 0;
    verticalScrollOffset = 0;
    horizontalScrollOffset = 0;
    resetSelection();
    renderer.setContent(content);
    if (verticalBar !is null) {
        verticalBar.setSelection(0);
    }
    if (horizontalBar !is null) {
        horizontalBar.setSelection(0);
    }
    resetCache(0, 0);
    setCaretLocation();
    super.redraw();
}
void resetCache(int firstLine, int count) {
    int maxLineIndex = renderer.maxWidthLineIndex;
    renderer.reset(firstLine, count);
    renderer.calculateClientArea();
    if (0 <= maxLineIndex && maxLineIndex < content.getLineCount()) {
        renderer.calculate(maxLineIndex, 1);
    }
    setScrollBars(true);
    if (!isFixedLineHeight()) {
        if (topIndex > firstLine) {
            verticalScrollOffset = -1;
        }
        renderer.calculateIdle();
    }
}
/**
 * Resets the selection.
 */
void resetSelection() {
    selection.x = selection.y = caretOffset;
    selectionAnchor = -1;
}

public override void scroll(int destX, int destY, int x, int y, int width, int height, bool all) {
    super.scroll(destX, destY, x, y, width, height, false);
    if (all) {
        int deltaX = destX - x, deltaY = destY - y;
        Control[] children = getChildren();
        for (int i=0; i<children.length; i++) {
            Control child = children[i];
            Rectangle rect = child.getBounds();
            child.setLocation(rect.x + deltaX, rect.y + deltaY);
        }
    }
}

/**
 * Scrolls the widget horizontally.
 *
 * @param pixels number of pixels to scroll, > 0 = scroll left,
 *  < 0 scroll right
 * @param adjustScrollBar
 *  true= the scroll thumb will be moved to reflect the new scroll offset.
 *  false = the scroll thumb will not be moved
 * @return
 *  true=the widget was scrolled
 *  false=the widget was not scrolled, the given offset is not valid.
 */
bool scrollHorizontal(int pixels, bool adjustScrollBar) {
    if (pixels is 0) {
        return false;
    }
    ScrollBar horizontalBar = getHorizontalBar();
    if (horizontalBar !is null && adjustScrollBar) {
        horizontalBar.setSelection(horizontalScrollOffset + pixels);
    }
    int scrollHeight = clientAreaHeight - topMargin - bottomMargin;
    if (pixels > 0) {
        int sourceX = leftMargin + pixels;
        int scrollWidth = clientAreaWidth - sourceX - rightMargin;
        if (scrollWidth > 0) {
            scroll(leftMargin, topMargin, sourceX, topMargin, scrollWidth, scrollHeight, true);
        }
        if (sourceX > scrollWidth) {
            super.redraw(leftMargin + scrollWidth, topMargin, pixels - scrollWidth, scrollHeight, true);
        }
    } else {
        int destinationX = leftMargin - pixels;
        int scrollWidth = clientAreaWidth - destinationX - rightMargin;
        if (scrollWidth > 0) {
            scroll(destinationX, topMargin, leftMargin, topMargin, scrollWidth, scrollHeight, true);
        }
        if (destinationX > scrollWidth) {
            super.redraw(leftMargin + scrollWidth, topMargin, -pixels - scrollWidth, scrollHeight, true);
        }
    }
    horizontalScrollOffset += pixels;
    setCaretLocation();
    return true;
}
/**
 * Scrolls the widget vertically.
 *
 * @param pixel the new vertical scroll offset
 * @param adjustScrollBar
 *  true= the scroll thumb will be moved to reflect the new scroll offset.
 *  false = the scroll thumb will not be moved
 * @return
 *  true=the widget was scrolled
 *  false=the widget was not scrolled
 */
bool scrollVertical(int pixels, bool adjustScrollBar) {
    if (pixels is 0) {
        return false;
    }
    if (verticalScrollOffset !is -1) {
        ScrollBar verticalBar = getVerticalBar();
        if (verticalBar !is null && adjustScrollBar) {
            verticalBar.setSelection(verticalScrollOffset + pixels);
        }
        int scrollWidth = clientAreaWidth - leftMargin - rightMargin;
        if (pixels > 0) {
            int sourceY = topMargin + pixels;
            int scrollHeight = clientAreaHeight - sourceY - bottomMargin;
            if (scrollHeight > 0) {
                scroll(leftMargin, topMargin, leftMargin, sourceY, scrollWidth, scrollHeight, true);
            }
            if (sourceY > scrollHeight) {
                int redrawY = Math.max(0, topMargin + scrollHeight);
                int redrawHeight = Math.min(clientAreaHeight, pixels - scrollHeight);
                super.redraw(leftMargin, redrawY, scrollWidth, redrawHeight, true);
            }
        } else {
            int destinationY = topMargin - pixels;
            int scrollHeight = clientAreaHeight - destinationY - bottomMargin;
            if (scrollHeight > 0) {
                scroll(leftMargin, destinationY, leftMargin, topMargin, scrollWidth, scrollHeight, true);
            }
            if (destinationY > scrollHeight) {
                int redrawY = Math.max(0, topMargin + scrollHeight);
                int redrawHeight = Math.min(clientAreaHeight, -pixels - scrollHeight);
                super.redraw(leftMargin, redrawY, scrollWidth, redrawHeight, true);
            }
        }
        verticalScrollOffset += pixels;
        calculateTopIndex(pixels);
    } else {
        calculateTopIndex(pixels);
        super.redraw();
    }
    setCaretLocation();
    return true;
}
void scrollText(int srcY, int destY) {
    if (srcY is destY) return;
    int deltaY = destY - srcY;
    int scrollWidth = clientAreaWidth - leftMargin - rightMargin, scrollHeight;
    if (deltaY > 0) {
        scrollHeight = clientAreaHeight - srcY - bottomMargin;
    } else {
        scrollHeight = clientAreaHeight - destY - bottomMargin;
    }
    scroll(leftMargin, destY, leftMargin, srcY, scrollWidth, scrollHeight, true);
    if ((0 < srcY + scrollHeight) && (topMargin > srcY)) {
        super.redraw(leftMargin, deltaY, scrollWidth, topMargin, false);
    }
    if ((0 < destY + scrollHeight) && (topMargin > destY)) {
        super.redraw(leftMargin, 0, scrollWidth, topMargin, false);
    }
    if ((clientAreaHeight - bottomMargin < srcY + scrollHeight) && (clientAreaHeight > srcY)) {
        super.redraw(leftMargin, clientAreaHeight - bottomMargin + deltaY, scrollWidth, bottomMargin, false);
    }
    if ((clientAreaHeight - bottomMargin < destY + scrollHeight) && (clientAreaHeight > destY)) {
        super.redraw(leftMargin, clientAreaHeight - bottomMargin, scrollWidth, bottomMargin, false);
    }
}
/**
 * Selects all the text.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void selectAll() {
    checkWidget();
    setSelection(0, Math.max(getCharCount(),0));
}
/**
 * Replaces/inserts text as defined by the event.
 *
 * @param event the text change event.
 *  <ul>
 *  <li>event.start - the replace start offset</li>
 *  <li>event.end - the replace end offset</li>
 *  <li>event.text - the new text</li>
 *  </ul>
 */
void sendKeyEvent(Event event) {
    if (editable) {
        modifyContent(event, true);
    }
}
/**
 * Returns a StyledTextEvent that can be used to request data such
 * as styles and background color for a line.
 * <p>
 * The specified line may be a visual (wrapped) line if in word
 * wrap mode. The returned object will always be for a logical
 * (unwrapped) line.
 * </p>
 *
 * @param lineOffset offset of the line. This may be the offset of
 *  a visual line if the widget is in word wrap mode.
 * @param line line text. This may be the text of a visual line if
 *  the widget is in word wrap mode.
 * @return StyledTextEvent that can be used to request line data
 *  for the given line.
 */
StyledTextEvent sendLineEvent(int eventType, int lineOffset, String line) {
    StyledTextEvent event = null;
    if (isListening(eventType)) {
        event = new StyledTextEvent(content);
        event.detail = lineOffset;
        event.text = line;
        event.alignment = alignment;
        event.indent = indent;
        event.justify = justify;
        notifyListeners(eventType, event);
    }
    return event;
}
void sendModifyEvent(Event event) {
    Accessible accessible = getAccessible();
    if (event.text.length is 0) {
        accessible.textChanged(ACC.TEXT_DELETE, event.start, event.end - event.start);
    } else {
        if (event.start is event.end) {
            accessible.textChanged(ACC.TEXT_INSERT, event.start, event.text.length);
        } else {
            accessible.textChanged(ACC.TEXT_DELETE, event.start, event.end - event.start);
            accessible.textChanged(ACC.TEXT_INSERT, event.start, event.text.length);
        }
    }
    notifyListeners(SWT.Modify, event);
}
/**
 * Sends the specified selection event.
 */
void sendSelectionEvent() {
    getAccessible().textSelectionChanged();
    Event event = new Event();
    event.x = selection.x;
    event.y = selection.y;
    notifyListeners(SWT.Selection, event);
}
int sendWordBoundaryEvent(int eventType, int movement, int offset, int newOffset, String lineText, int lineOffset) {
    if (isListening(eventType)) {
        StyledTextEvent event = new StyledTextEvent(content);
        event.detail = lineOffset;
        event.text = lineText;
        event.count = movement;
        event.start = offset;
        event.end = newOffset;
        notifyListeners(eventType, event);
        offset = event.end;
        if (offset !is newOffset) {
            int length = getCharCount();
            if (offset < 0) {
                offset = 0;
            } else if (offset > length) {
                offset = length;
            } else {
                if (isLineDelimiter(offset)) {
                    SWT.error(SWT.ERROR_INVALID_ARGUMENT);
                }
            }
        }
        return offset;
    }
    return newOffset;
}
/**
 * Sets the alignment of the widget. The argument should be one of <code>SWT.LEFT</code>,
 * <code>SWT.CENTER</code> or <code>SWT.RIGHT</code>. The alignment applies for all lines.
 * </p><p>
 * Note that if <code>SWT.MULTI</code> is set, then <code>SWT.WRAP</code> must also be set
 * in order to stabilize the right edge before setting alignment.
 * </p>
 *
 * @param alignment the new alignment
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #setLineAlignment(int, int, int)
 *
 * @since 3.2
 */
public void setAlignment(int alignment) {
    checkWidget();
    alignment &= (SWT.LEFT | SWT.RIGHT | SWT.CENTER);
    if (alignment is 0 || this.alignment is alignment) return;
    this.alignment = alignment;
    resetCache(0, content.getLineCount());
    setCaretLocation();
    super.redraw();
}
/**
 * @see Control#setBackground(Color)
 */
public override void setBackground(Color color) {
    checkWidget();
    background = color;
    super.setBackground(color);
    super.redraw();
}
/**
 * Sets the receiver's caret.  Set the caret's height and location.
 *
 * </p>
 * @param caret the new caret for the receiver
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public override void setCaret(Caret caret) {
    checkWidget ();
    super.setCaret(caret);
    caretDirection = SWT.NULL;
    if (caret !is null) {
        setCaretLocation();
    }
}
/**
 * Sets the BIDI coloring mode.  When true the BIDI text display
 * algorithm is applied to segments of text that are the same
 * color.
 *
 * @param mode the new coloring mode
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @deprecated use BidiSegmentListener instead.
 */
public void setBidiColoring(bool mode) {
    checkWidget();
    bidiColoring = mode;
}
/**
 * Moves the Caret to the current caret offset.
 */
void setCaretLocation() {
    Point newCaretPos = getPointAtOffset(caretOffset);
    setCaretLocation(newCaretPos, getCaretDirection());
}
void setCaretLocation(Point location, int direction) {
    Caret caret = getCaret();
    if (caret !is null) {
        bool isDefaultCaret = caret is defaultCaret;
        int lineHeight = renderer.getLineHeight();
        int caretHeight = lineHeight;
        if (!isFixedLineHeight() && isDefaultCaret) {
            caretHeight = getBoundsAtOffset(caretOffset).height;
            if (caretHeight !is lineHeight) {
                direction = SWT.DEFAULT;
            }
        }
        int imageDirection = direction;
        if (isMirrored()) {
            if (imageDirection is SWT.LEFT) {
                imageDirection = SWT.RIGHT;
            } else if (imageDirection is SWT.RIGHT) {
                imageDirection = SWT.LEFT;
            }
        }
        if (isDefaultCaret && imageDirection is SWT.RIGHT) {
            location.x -= (caret.getSize().x - 1);
        }
        if (isDefaultCaret) {
            caret.setBounds(location.x, location.y, caretWidth, caretHeight);
        } else {
            caret.setLocation(location);
        }
        getAccessible().textCaretMoved(getCaretOffset());
        if (direction !is caretDirection) {
            caretDirection = direction;
            if (isDefaultCaret) {
                if (imageDirection is SWT.DEFAULT) {
                    defaultCaret.setImage(null);
                } else if (imageDirection is SWT.LEFT) {
                    defaultCaret.setImage(leftCaretBitmap);
                } else if (imageDirection is SWT.RIGHT) {
                    defaultCaret.setImage(rightCaretBitmap);
                }
            }
            if (caretDirection is SWT.LEFT) {
                BidiUtil.setKeyboardLanguage(BidiUtil.KEYBOARD_NON_BIDI);
            } else if (caretDirection is SWT.RIGHT) {
                BidiUtil.setKeyboardLanguage(BidiUtil.KEYBOARD_BIDI);
            }
        }
    }
    columnX = location.x;
}
/**
 * Sets the caret offset.
 *
 * @param offset caret offset, relative to the first character in the text.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when either the start or the end of the selection range is inside a
 * multi byte line delimiter (and thus neither clearly in front of or after the line delimiter)
 * </ul>
 */
public void setCaretOffset(int offset) {
    checkWidget();
    int length = getCharCount();
    if (length > 0 && offset !is caretOffset) {
        if (offset < 0) {
            caretOffset = 0;
        } else if (offset > length) {
            caretOffset = length;
        } else {
            if (isLineDelimiter(offset)) {
                // offset is inside a multi byte line delimiter. This is an
                // illegal operation and an exception is thrown. Fixes 1GDKK3R
                SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            }
            caretOffset = offset;
        }
        caretAlignment = PREVIOUS_OFFSET_TRAILING;
        // clear the selection if the caret is moved.
        // don't notify listeners about the selection change.
        clearSelection(false);
    }
    setCaretLocation();
}
/**
 * Copies the specified text range to the clipboard.  The text will be placed
 * in the clipboard in plain text format and RTF format.
 *
 * @param start start index of the text
 * @param length length of text to place in clipboard
 *
 * @exception SWTError, see Clipboard.setContents
 * @see org.eclipse.swt.dnd.Clipboard#setContents
 */
void setClipboardContent(int start, int length, int clipboardType) {
    if (clipboardType is DND.SELECTION_CLIPBOARD && !(IS_MOTIF || IS_GTK)) return;
    TextTransfer plainTextTransfer = TextTransfer.getInstance();
    TextWriter plainTextWriter = new TextWriter(start, length);
    String plainText = getPlatformDelimitedText(plainTextWriter);
    Object[] data;
    Transfer[] types;
    if (clipboardType is DND.SELECTION_CLIPBOARD) {
        data = [ cast(Object) new ArrayWrapperString(plainText) ];
        types = [plainTextTransfer];
    } else {
        RTFTransfer rtfTransfer = RTFTransfer.getInstance();
        RTFWriter rtfWriter = new RTFWriter(start, length);
        String rtfText = getPlatformDelimitedText(rtfWriter);
        data = [ cast(Object) new ArrayWrapperString(rtfText), new ArrayWrapperString(plainText) ];
        types = [ cast(Transfer)rtfTransfer, plainTextTransfer];
    }
    clipboard.setContents(data, types, clipboardType);
}
/**
 * Sets the content implementation to use for text storage.
 *
 * @param newContent StyledTextContent implementation to use for text storage.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void setContent(StyledTextContent newContent) {
    checkWidget();
    if (newContent is null) {
        SWT.error(SWT.ERROR_NULL_ARGUMENT);
    }
    if (content !is null) {
        content.removeTextChangeListener(textChangeListener);
    }
    content = newContent;
    content.addTextChangeListener(textChangeListener);
    reset();
}
/**
 * Sets the receiver's cursor to the cursor specified by the
 * argument.  Overridden to handle the null case since the
 * StyledText widget uses an ibeam as its default cursor.
 *
 * @see Control#setCursor(Cursor)
 */
public override void setCursor (Cursor cursor) {
    if (cursor is null) {
        Display display = getDisplay();
        super.setCursor(display.getSystemCursor(SWT.CURSOR_IBEAM));
    } else {
        super.setCursor(cursor);
    }
}
/**
 * Sets whether the widget : double click mouse behavior.
 * </p>
 *
 * @param enable if true double clicking a word selects the word, if false
 *  double clicks have the same effect as regular mouse clicks.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setDoubleClickEnabled(bool enable) {
    checkWidget();
    doubleClickEnabled = enable;
}
public override void setDragDetect (bool dragDetect_) {
    checkWidget ();
    this.dragDetect_ = dragDetect_;
}
/**
 * Sets whether the widget content can be edited.
 * </p>
 *
 * @param editable if true content can be edited, if false content can not be
 *  edited
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setEditable(bool editable) {
    checkWidget();
    this.editable = editable;
}
/**
 * Sets a new font to render text with.
 * <p>
 * <b>NOTE:</b> Italic fonts are not supported unless they have no overhang
 * and the same baseline as regular fonts.
 * </p>
 *
 * @param font new font
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public override void setFont(Font font) {
    checkWidget();
    int oldLineHeight = renderer.getLineHeight();
    super.setFont(font);
    renderer.setFont(getFont(), tabLength);
    // keep the same top line visible. fixes 5815
    if (isFixedLineHeight()) {
        int lineHeight = renderer.getLineHeight();
        if (lineHeight !is oldLineHeight) {
            int vscroll = (getVerticalScrollOffset() * lineHeight / oldLineHeight) - getVerticalScrollOffset();
            scrollVertical(vscroll, true);
        }
    }
    resetCache(0, content.getLineCount());
    claimBottomFreeSpace();
    calculateScrollBars();
    if (isBidiCaret()) createCaretBitmaps();
    caretDirection = SWT.NULL;
    setCaretLocation();
    super.redraw();
}
public override void setForeground(Color color) {
    checkWidget();
    foreground = color;
    super.setForeground(getForeground());
    super.redraw();
}
/**
 * Sets the horizontal scroll offset relative to the start of the line.
 * Do nothing if there is no text set.
 * <p>
 * <b>NOTE:</b> The horizontal index is reset to 0 when new text is set in the
 * widget.
 * </p>
 *
 * @param offset horizontal scroll offset relative to the start
 *  of the line, measured in character increments starting at 0, if
 *  equal to 0 the content is not scrolled, if > 0 = the content is scrolled.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setHorizontalIndex(int offset) {
    checkWidget();
    if (getCharCount() is 0) {
        return;
    }
    if (offset < 0) {
        offset = 0;
    }
    offset *= getHorizontalIncrement();
    // allow any value if client area width is unknown or 0.
    // offset will be checked in resize handler.
    // don't use isVisible since width is known even if widget
    // is temporarily invisible
    if (clientAreaWidth > 0) {
        int width = renderer.getWidth();
        // prevent scrolling if the content fits in the client area.
        // align end of longest line with right border of client area
        // if offset is out of range.
        if (offset > width - clientAreaWidth) {
            offset = Math.max(0, width - clientAreaWidth);
        }
    }
    scrollHorizontal(offset - horizontalScrollOffset, true);
}
/**
 * Sets the horizontal pixel offset relative to the start of the line.
 * Do nothing if there is no text set.
 * <p>
 * <b>NOTE:</b> The horizontal pixel offset is reset to 0 when new text
 * is set in the widget.
 * </p>
 *
 * @param pixel horizontal pixel offset relative to the start
 *  of the line.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.0
 */
public void setHorizontalPixel(int pixel) {
    checkWidget();
    if (getCharCount() is 0) {
        return;
    }
    if (pixel < 0) {
        pixel = 0;
    }
    // allow any value if client area width is unknown or 0.
    // offset will be checked in resize handler.
    // don't use isVisible since width is known even if widget
    // is temporarily invisible
    if (clientAreaWidth > 0) {
        int width = renderer.getWidth();
        // prevent scrolling if the content fits in the client area.
        // align end of longest line with right border of client area
        // if offset is out of range.
        if (pixel > width - clientAreaWidth) {
            pixel = Math.max(0, width - clientAreaWidth);
        }
    }
    scrollHorizontal(pixel - horizontalScrollOffset, true);
}
/**
 * Sets the line indentation of the widget.
 * <p>
 * It is the amount of blank space, in pixels, at the beginning of each line.
 * When a line wraps in several lines only the first one is indented.
 * </p>
 *
 * @param indent the new indent
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #setLineIndent(int, int, int)
 *
 * @since 3.2
 */
public void setIndent(int indent) {
    checkWidget();
    if (this.indent is indent || indent < 0) return;
    this.indent = indent;
    resetCache(0, content.getLineCount());
    setCaretLocation();
    super.redraw();
}
/**
 * Sets whether the widget should justify lines.
 *
 * @param justify whether lines should be justified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see #setLineJustify(int, int, bool)
 *
 * @since 3.2
 */
public void setJustify(bool justify) {
    checkWidget();
    if (this.justify is justify) return;
    this.justify = justify;
    resetCache(0, content.getLineCount());
    setCaretLocation();
    super.redraw();
}
/**
 * Maps a key to an action.
 * <p>
 * One action can be associated with N keys. However, each key can only
 * have one action (key:action is N:1 relation).
 * </p>
 *
 * @param key a key code defined in SWT.java or a character.
 *  Optionally ORd with a state mask.  Preferred state masks are one or more of
 *  SWT.MOD1, SWT.MOD2, SWT.MOD3, since these masks account for modifier platform
 *  differences.  However, there may be cases where using the specific state masks
 *  (i.e., SWT.CTRL, SWT.SHIFT, SWT.ALT, SWT.COMMAND) makes sense.
 * @param action one of the predefined actions defined in ST.java.
 *  Use SWT.NULL to remove a key binding.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setKeyBinding(int key, int action) {
    checkWidget();
    int modifierValue = key & SWT.MODIFIER_MASK;
    char keyChar = cast(char)(key & SWT.KEY_MASK);
    if (Compatibility.isLetter(keyChar)) {
        // make the keybinding case insensitive by adding it
        // in its upper and lower case form
        char ch = cast(char) CharacterToUpper(keyChar);
        int newKey = ch | modifierValue;
        if (action is SWT.NULL) {
            keyActionMap.remove(newKey);
        } else {
            keyActionMap[newKey] = action;
        }
        ch = cast(char) CharacterToLower(keyChar);
        newKey = ch | modifierValue;
        if (action is SWT.NULL) {
            keyActionMap.remove(newKey);
        } else {
            keyActionMap[newKey] = action;
        }
    } else {
        if (action is SWT.NULL) {
            keyActionMap.remove(key);
        } else {
            keyActionMap[key]=action;
        }
    }
}
/**
 * Sets the alignment of the specified lines. The argument should be one of <code>SWT.LEFT</code>,
 * <code>SWT.CENTER</code> or <code>SWT.RIGHT</code>.
 * <p><p>
 * Note that if <code>SWT.MULTI</code> is set, then <code>SWT.WRAP</code> must also be set
 * in order to stabilize the right edge before setting alignment.
 * </p>
 * Should not be called if a LineStyleListener has been set since the listener
 * maintains the line attributes.
 * </p><p>
 * All line attributes are maintained relative to the line text, not the
 * line index that is specified in this method call.
 * During text changes, when entire lines are inserted or removed, the line
 * attributes that are associated with the lines after the change
 * will "move" with their respective text. An entire line is defined as
 * extending from the first character on a line to the last and including the
 * line delimiter.
 * </p><p>
 * When two lines are joined by deleting a line delimiter, the top line
 * attributes take precedence and the attributes of the bottom line are deleted.
 * For all other text changes line attributes will remain unchanged.
 *
 * @param startLine first line the alignment is applied to, 0 based
 * @param lineCount number of lines the alignment applies to.
 * @param alignment line alignment
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the specified line range is invalid</li>
 * </ul>
 * @see #setAlignment(int)
 * @since 3.2
 */
public void setLineAlignment(int startLine, int lineCount, int alignment) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (startLine < 0 || startLine + lineCount > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }

    renderer.setLineAlignment(startLine, lineCount, alignment);
    resetCache(startLine, lineCount);
    redrawLines(startLine, lineCount);
    int caretLine = getCaretLine();
    if (startLine <= caretLine && caretLine < startLine + lineCount) {
        setCaretLocation();
    }
}
/**
 * Sets the background color of the specified lines.
 * <p>
 * The background color is drawn for the width of the widget. All
 * line background colors are discarded when setText is called.
 * The text background color if defined in a StyleRange overlays the
 * line background color.
 * </p><p>
 * Should not be called if a LineBackgroundListener has been set since the
 * listener maintains the line backgrounds.
 * </p><p>
 * All line attributes are maintained relative to the line text, not the
 * line index that is specified in this method call.
 * During text changes, when entire lines are inserted or removed, the line
 * attributes that are associated with the lines after the change
 * will "move" with their respective text. An entire line is defined as
 * extending from the first character on a line to the last and including the
 * line delimiter.
 * </p><p>
 * When two lines are joined by deleting a line delimiter, the top line
 * attributes take precedence and the attributes of the bottom line are deleted.
 * For all other text changes line attributes will remain unchanged.
 * </p>
 *
 * @param startLine first line the color is applied to, 0 based
 * @param lineCount number of lines the color applies to.
 * @param background line background color
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the specified line range is invalid</li>
 * </ul>
 */
public void setLineBackground(int startLine, int lineCount, Color background) {
    checkWidget();
    if (isListening(LineGetBackground)) return;
    if (startLine < 0 || startLine + lineCount > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    if (background !is null) {
        renderer.setLineBackground(startLine, lineCount, background);
    } else {
        renderer.clearLineBackground(startLine, lineCount);
    }
    redrawLines(startLine, lineCount);
}
/**
 * Sets the bullet of the specified lines.
 * <p>
 * Should not be called if a LineStyleListener has been set since the listener
 * maintains the line attributes.
 * </p><p>
 * All line attributes are maintained relative to the line text, not the
 * line index that is specified in this method call.
 * During text changes, when entire lines are inserted or removed, the line
 * attributes that are associated with the lines after the change
 * will "move" with their respective text. An entire line is defined as
 * extending from the first character on a line to the last and including the
 * line delimiter.
 * </p><p>
 * When two lines are joined by deleting a line delimiter, the top line
 * attributes take precedence and the attributes of the bottom line are deleted.
 * For all other text changes line attributes will remain unchanged.
 * </p>
 *
 * @param startLine first line the bullet is applied to, 0 based
 * @param lineCount number of lines the bullet applies to.
 * @param bullet line bullet
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the specified line range is invalid</li>
 * </ul>
 * @since 3.2
 */
public void setLineBullet(int startLine, int lineCount, Bullet bullet) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (startLine < 0 || startLine + lineCount > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }

    renderer.setLineBullet(startLine, lineCount, bullet);
    resetCache(startLine, lineCount);
    redrawLines(startLine, lineCount);
    int caretLine = getCaretLine();
    if (startLine <= caretLine && caretLine < startLine + lineCount) {
        setCaretLocation();
    }
}
void setVariableLineHeight () {
    if (!fixedLineHeight) return;
    fixedLineHeight = false;
    renderer.calculateIdle();
}
/**
 * Sets the indent of the specified lines.
 * <p>
 * Should not be called if a LineStyleListener has been set since the listener
 * maintains the line attributes.
 * </p><p>
 * All line attributes are maintained relative to the line text, not the
 * line index that is specified in this method call.
 * During text changes, when entire lines are inserted or removed, the line
 * attributes that are associated with the lines after the change
 * will "move" with their respective text. An entire line is defined as
 * extending from the first character on a line to the last and including the
 * line delimiter.
 * </p><p>
 * When two lines are joined by deleting a line delimiter, the top line
 * attributes take precedence and the attributes of the bottom line are deleted.
 * For all other text changes line attributes will remain unchanged.
 * </p>
 *
 * @param startLine first line the indent is applied to, 0 based
 * @param lineCount number of lines the indent applies to.
 * @param indent line indent
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the specified line range is invalid</li>
 * </ul>
 * @see #setIndent(int)
 * @since 3.2
 */
public void setLineIndent(int startLine, int lineCount, int indent) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (startLine < 0 || startLine + lineCount > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }

    renderer.setLineIndent(startLine, lineCount, indent);
    resetCache(startLine, lineCount);
    redrawLines(startLine, lineCount);
    int caretLine = getCaretLine();
    if (startLine <= caretLine && caretLine < startLine + lineCount) {
        setCaretLocation();
    }
}
/**
 * Sets the justify of the specified lines.
 * <p>
 * Should not be called if a LineStyleListener has been set since the listener
 * maintains the line attributes.
 * </p><p>
 * All line attributes are maintained relative to the line text, not the
 * line index that is specified in this method call.
 * During text changes, when entire lines are inserted or removed, the line
 * attributes that are associated with the lines after the change
 * will "move" with their respective text. An entire line is defined as
 * extending from the first character on a line to the last and including the
 * line delimiter.
 * </p><p>
 * When two lines are joined by deleting a line delimiter, the top line
 * attributes take precedence and the attributes of the bottom line are deleted.
 * For all other text changes line attributes will remain unchanged.
 * </p>
 *
 * @param startLine first line the justify is applied to, 0 based
 * @param lineCount number of lines the justify applies to.
 * @param justify true if lines should be justified
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when the specified line range is invalid</li>
 * </ul>
 * @see #setJustify(bool)
 * @since 3.2
 */
public void setLineJustify(int startLine, int lineCount, bool justify) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (startLine < 0 || startLine + lineCount > content.getLineCount()) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }

    renderer.setLineJustify(startLine, lineCount, justify);
    resetCache(startLine, lineCount);
    redrawLines(startLine, lineCount);
    int caretLine = getCaretLine();
    if (startLine <= caretLine && caretLine < startLine + lineCount) {
        setCaretLocation();
    }
}
/**
 * Sets the line spacing of the widget. The line spacing applies for all lines.
 *
 * @param lineSpacing the line spacing
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 3.2
 */
public void setLineSpacing(int lineSpacing) {
    checkWidget();
    if (this.lineSpacing is lineSpacing || lineSpacing < 0) return;
    this.lineSpacing = lineSpacing;
    setVariableLineHeight();
    resetCache(0, content.getLineCount());
    setCaretLocation();
    super.redraw();
}
void setMargins (int leftMargin, int topMargin, int rightMargin, int bottomMargin) {
    checkWidget();
    this.leftMargin = leftMargin;
    this.topMargin = topMargin;
    this.rightMargin = rightMargin;
    this.bottomMargin = bottomMargin;
    setCaretLocation();
}
/**
 * Flips selection anchor based on word selection direction.
 */
void setMouseWordSelectionAnchor() {
    if (clickCount > 1) {
        if (caretOffset < doubleClickSelection.x) {
            selectionAnchor = doubleClickSelection.y;
        } else if (caretOffset > doubleClickSelection.y) {
            selectionAnchor = doubleClickSelection.x;
        }
    }
}
/**
 * Sets the orientation of the receiver, which must be one
 * of the constants <code>SWT.LEFT_TO_RIGHT</code> or <code>SWT.RIGHT_TO_LEFT</code>.
 *
 * @param orientation new orientation style
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @since 2.1.2
 */
public void setOrientation(int orientation) {
    if ((orientation & (SWT.RIGHT_TO_LEFT | SWT.LEFT_TO_RIGHT)) is 0) {
        return;
    }
    if ((orientation & SWT.RIGHT_TO_LEFT) !is 0 && (orientation & SWT.LEFT_TO_RIGHT) !is 0) {
        return;
    }
    if ((orientation & SWT.RIGHT_TO_LEFT) !is 0 && isMirrored()) {
        return;
    }
    if ((orientation & SWT.LEFT_TO_RIGHT) !is 0 && !isMirrored()) {
        return;
    }
    if (!BidiUtil.setOrientation(this, orientation)) {
        return;
    }
    isMirrored_ = (orientation & SWT.RIGHT_TO_LEFT) !is 0;
    caretDirection = SWT.NULL;
    resetCache(0, content.getLineCount());
    setCaretLocation();
    keyActionMap = null;
    createKeyBindings();
    super.redraw();
}
/**
 * Adjusts the maximum and the page size of the scroll bars to
 * reflect content width/length changes.
 *
 * @param vertical indicates if the vertical scrollbar also needs to be set
 */
void setScrollBars(bool vertical) {
    int inactive = 1;
    if (vertical || !isFixedLineHeight()) {
        ScrollBar verticalBar = getVerticalBar();
        if (verticalBar !is null) {
            int maximum = renderer.getHeight();
            // only set the real values if the scroll bar can be used
            // (ie. because the thumb size is less than the scroll maximum)
            // avoids flashing on Motif, fixes 1G7RE1J and 1G5SE92
            if (clientAreaHeight < maximum) {
                verticalBar.setMaximum(maximum);
                verticalBar.setThumb(clientAreaHeight);
                verticalBar.setPageIncrement(clientAreaHeight);
            } else if (verticalBar.getThumb() !is inactive || verticalBar.getMaximum() !is inactive) {
                verticalBar.setValues(
                    verticalBar.getSelection(),
                    verticalBar.getMinimum(),
                    inactive,
                    inactive,
                    verticalBar.getIncrement(),
                    inactive);
            }
        }
    }
    ScrollBar horizontalBar = getHorizontalBar();
    if (horizontalBar !is null && horizontalBar.getVisible()) {
        int maximum = renderer.getWidth();
        // only set the real values if the scroll bar can be used
        // (ie. because the thumb size is less than the scroll maximum)
        // avoids flashing on Motif, fixes 1G7RE1J and 1G5SE92
        if (clientAreaWidth < maximum) {
            horizontalBar.setMaximum(maximum);
            horizontalBar.setThumb(clientAreaWidth - leftMargin - rightMargin);
            horizontalBar.setPageIncrement(clientAreaWidth - leftMargin - rightMargin);
        } else if (horizontalBar.getThumb() !is inactive || horizontalBar.getMaximum() !is inactive) {
            horizontalBar.setValues(
                horizontalBar.getSelection(),
                horizontalBar.getMinimum(),
                inactive,
                inactive,
                horizontalBar.getIncrement(),
                inactive);
        }
    }
}
/**
 * Sets the selection to the given position and scrolls it into view.  Equivalent to setSelection(start,start).
 *
 * @param start new caret position
 * @see #setSelection(int,int)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when either the start or the end of the selection range is inside a
 * multi byte line delimiter (and thus neither clearly in front of or after the line delimiter)
 * </ul>
 */
public void setSelection(int start) {
    // checkWidget test done in setSelectionRange
    setSelection(start, start);
}
/**
 * Sets the selection and scrolls it into view.
 * <p>
 * Indexing is zero based.  Text selections are specified in terms of
 * caret positions.  In a text widget that contains N characters, there are
 * N+1 caret positions, ranging from 0..N
 * </p>
 *
 * @param point x=selection start offset, y=selection end offset
 *  The caret will be placed at the selection start when x > y.
 * @see #setSelection(int,int)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_NULL_ARGUMENT when point is null</li>
 *   <li>ERROR_INVALID_ARGUMENT when either the start or the end of the selection range is inside a
 * multi byte line delimiter (and thus neither clearly in front of or after the line delimiter)
 * </ul>
 */
public void setSelection(Point point) {
    checkWidget();
    if (point is null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
    setSelection(point.x, point.y);
}
/**
 * Sets the receiver's selection background color to the color specified
 * by the argument, or to the default system color for the control
 * if the argument is null.
 *
 * @param color the new color (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.1
 */
public void setSelectionBackground (Color color) {
    checkWidget ();
    if (color !is null) {
        if (color.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    selectionBackground = color;
    super.redraw();
}
/**
 * Sets the receiver's selection foreground color to the color specified
 * by the argument, or to the default system color for the control
 * if the argument is null.
 * <p>
 * Note that this is a <em>HINT</em>. Some platforms do not allow the application
 * to change the selection foreground color.
 * </p>
 * @param color the new color (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.1
 */
public void setSelectionForeground (Color color) {
    checkWidget ();
    if (color !is null) {
        if (color.isDisposed()) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    selectionForeground = color;
    super.redraw();
}
/**
 * Sets the selection and scrolls it into view.
 * <p>
 * Indexing is zero based.  Text selections are specified in terms of
 * caret positions.  In a text widget that contains N characters, there are
 * N+1 caret positions, ranging from 0..N
 * </p>
 *
 * @param start selection start offset. The caret will be placed at the
 *  selection start when start > end.
 * @param end selection end offset
 * @see #setSelectionRange(int,int)
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when either the start or the end of the selection range is inside a
 * multi byte line delimiter (and thus neither clearly in front of or after the line delimiter)
 * </ul>
 */
public void setSelection(int start, int end) {
    setSelectionRange(start, end - start);
    showSelection();
}
/**
 * Sets the selection.
 * <p>
 * The new selection may not be visible. Call showSelection to scroll
 * the selection into view.
 * </p>
 *
 * @param start offset of the first selected character, start >= 0 must be true.
 * @param length number of characters to select, 0 <= start + length
 *  <= getCharCount() must be true.
 *  A negative length places the caret at the selection start.
 * @param sendEvent a Selection event is sent when set to true and when
 *  the selection is reset.
 */
void setSelection(int start, int length, bool sendEvent) {
    int end = start + length;
    start = content.utf8AdjustOffset(start);
    end = content.utf8AdjustOffset(end);
    if (start > end) {
        int temp = end;
        end = start;
        start = temp;
    }
    // is the selection range different or is the selection direction
    // different?
    if (selection.x !is start || selection.y !is end ||
        (length > 0 && selectionAnchor !is selection.x) ||
        (length < 0 && selectionAnchor !is selection.y)) {
        clearSelection(sendEvent);
        if (length < 0) {
            selectionAnchor = selection.y = end;
            caretOffset = selection.x = start;
        } else {
            selectionAnchor = selection.x = start;
            caretOffset = selection.y = end;
        }
        caretAlignment = PREVIOUS_OFFSET_TRAILING;
        internalRedrawRange(selection.x, selection.y - selection.x);
    }
}
/**
 * Sets the selection.
 * <p>
 * The new selection may not be visible. Call showSelection to scroll the selection
 * into view. A negative length places the caret at the visual start of the selection.
 * </p>
 *
 * @param start offset of the first selected character
 * @param length number of characters to select
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_ARGUMENT when either the start or the end of the selection range is inside a
 * multi byte line delimiter (and thus neither clearly in front of or after the line delimiter)
 * </ul>
 */
public void setSelectionRange(int start, int length) {
    checkWidget();
    int contentLength = getCharCount();
    start = Math.max(0, Math.min (start, contentLength));
    int end = start + length;
    if (end < 0) {
        length = -start;
    } else {
        if (end > contentLength) length = contentLength - start;
    }
    if (isLineDelimiter(start) || isLineDelimiter(start + length)) {
        // the start offset or end offset of the selection range is inside a
        // multi byte line delimiter. This is an illegal operation and an exception
        // is thrown. Fixes 1GDKK3R
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    setSelection(start, length, false);
    setCaretLocation();
}
/**
 * Adds the specified style.
 * <p>
 * The new style overwrites existing styles for the specified range.
 * Existing style ranges are adjusted if they partially overlap with
 * the new style. To clear an individual style, call setStyleRange
 * with a StyleRange that has null attributes.
 * </p><p>
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param range StyleRange object containing the style information.
 * Overwrites the old style in the given range. May be null to delete
 * all styles.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_INVALID_RANGE when the style range is outside the valid range (> getCharCount())</li>
 * </ul>
 */
public void setStyleRange(StyleRange range) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (range !is null) {
        if (range.isUnstyled()) {
            setStyleRanges(range.start, range.length, null, null, false);
        } else {
            setStyleRanges(range.start, 0, null, [range], false);
        }
    } else {
        setStyleRanges(0, 0, null, null, true);
    }
}
/**
 * Clears the styles in the range specified by <code>start</code> and
 * <code>length</code> and adds the new styles.
 * <p>
 * The ranges array contains start and length pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] with length ranges[n+1] uses the style
 * at styles[n/2].  The range fields within each StyleRange are ignored.
 * If ranges or styles is null, the specified range is cleared.
 * </p><p>
 * Note: It is expected that the same instance of a StyleRange will occur
 * multiple times within the styles array, reducing memory usage.
 * </p><p>
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param start offset of first character where styles will be deleted
 * @param length length of the range to delete styles in
 * @param ranges the array of ranges.  The ranges must not overlap and must be in order.
 * @param styles the array of StyleRanges.  The range fields within the StyleRange are unused.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when an element in the styles array is null</li>
 *    <li>ERROR_INVALID_RANGE when the number of ranges and style do not match (ranges.length * 2 is styles.length)</li>
 *    <li>ERROR_INVALID_RANGE when a range is outside the valid range (> getCharCount() or less than zero)</li>
 *    <li>ERROR_INVALID_RANGE when a range overlaps</li>
 * </ul>
 *
 * @since 3.2
 */
public void setStyleRanges(int start, int length, int[] ranges, StyleRange[] styles) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (ranges is null || styles is null) {
        setStyleRanges(start, length, null, null, false);
    } else {
        setStyleRanges(start, length, ranges, styles, false);
    }
}
/**
 * Sets styles to be used for rendering the widget content.
 * <p>
 * All styles in the widget will be replaced with the given set of ranges and styles.
 * The ranges array contains start and length pairs.  Each pair refers to
 * the corresponding style in the styles array.  For example, the pair
 * that starts at ranges[n] with length ranges[n+1] uses the style
 * at styles[n/2].  The range fields within each StyleRange are ignored.
 * If either argument is null, the styles are cleared.
 * </p><p>
 * Note: It is expected that the same instance of a StyleRange will occur
 * multiple times within the styles array, reducing memory usage.
 * </p><p>
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param ranges the array of ranges.  The ranges must not overlap and must be in order.
 * @param styles the array of StyleRanges.  The range fields within the StyleRange are unused.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when an element in the styles array is null</li>
 *    <li>ERROR_INVALID_RANGE when the number of ranges and style do not match (ranges.length * 2 is styles.length)</li>
 *    <li>ERROR_INVALID_RANGE when a range is outside the valid range (> getCharCount() or less than zero)</li>
 *    <li>ERROR_INVALID_RANGE when a range overlaps</li>
 * </ul>
 *
 * @since 3.2
 */
public void setStyleRanges(int[] ranges, StyleRange[] styles) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    if (ranges is null || styles is null) {
        setStyleRanges(0, 0, null, null, true);
    } else {
        setStyleRanges(0, 0, ranges, styles, true);
    }
}
void setStyleRanges(int start, int length, int[] ranges, StyleRange[] styles, bool reset) {
    int charCount = content.getCharCount();
    int end = start + length;
    if (start > end || start < 0) {
        SWT.error(SWT.ERROR_INVALID_RANGE);
    }
    if (styles !is null) {
        if (end > charCount) {
            SWT.error(SWT.ERROR_INVALID_RANGE);
        }
        if (ranges !is null) {
            if (ranges.length !is styles.length << 1) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
        }
        int lastOffset = 0;
        bool variableHeight = false;
        for (int i = 0; i < styles.length; i ++) {
            if (styles[i] is null) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            int rangeStart, rangeLength;
            if (ranges !is null) {
                rangeStart = ranges[i << 1];
                rangeLength = ranges[(i << 1) + 1];
            } else {
                rangeStart = styles[i].start;
                rangeLength = styles[i].length;
            }
            if (rangeLength < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            if (!(0 <= rangeStart && rangeStart + rangeLength <= charCount)) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            if (lastOffset > rangeStart) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            variableHeight |= styles[i].isVariableHeight();
            lastOffset = rangeStart + rangeLength;
        }
        if (variableHeight) setVariableLineHeight();
    }
    int rangeStart = start, rangeEnd = end;
    if (styles !is null && styles.length > 0) {
        if (ranges !is null) {
            rangeStart = ranges[0];
            rangeEnd = ranges[ranges.length - 2] + ranges[ranges.length - 1];
        } else {
            rangeStart = styles[0].start;
            rangeEnd = styles[styles.length - 1].start + styles[styles.length - 1].length;
        }
    }
    int lastLineBottom = 0;
    if (!isFixedLineHeight() && !reset) {
        int lineEnd = content.getLineAtOffset(Math.max(end, rangeEnd));
        int partialTopIndex = getPartialTopIndex();
        int partialBottomIndex = getPartialBottomIndex();
        if (partialTopIndex <= lineEnd && lineEnd <= partialBottomIndex) {
            lastLineBottom = getLinePixel(lineEnd + 1);
        }
    }
    if (reset) {
        renderer.setStyleRanges(null, null);
    } else {
        renderer.updateRanges(start, length, length);
    }
    if (styles !is null && styles.length > 0) {
        renderer.setStyleRanges(ranges, styles);
    }
    if (reset) {
        resetCache(0, content.getLineCount());
        super.redraw();
    } else {
        int lineStart = content.getLineAtOffset(Math.min(start, rangeStart));
        int lineEnd = content.getLineAtOffset(Math.max(end, rangeEnd));
        resetCache(lineStart, lineEnd - lineStart + 1);
        int partialTopIndex = getPartialTopIndex();
        int partialBottomIndex = getPartialBottomIndex();
        if (!(lineStart > partialBottomIndex || lineEnd < partialTopIndex)) {
            int y = 0;
            int height = clientAreaHeight;
            if (partialTopIndex <= lineStart && lineStart <= partialBottomIndex) {
                int lineTop = Math.max(y, getLinePixel(lineStart));
                y = lineTop;
                height -= lineTop;
            }
            if (partialTopIndex <= lineEnd && lineEnd <= partialBottomIndex) {
                int newLastLineBottom = getLinePixel(lineEnd + 1);
                if (!isFixedLineHeight()) {
                    scrollText(lastLineBottom, newLastLineBottom);
                }
                height = newLastLineBottom - y;
            }
            super.redraw(0, y, clientAreaWidth, height, false);
        }
    }
    setCaretLocation();
}
/**
 * Sets styles to be used for rendering the widget content. All styles
 * in the widget will be replaced with the given set of styles.
 * <p>
 * Note: Because a StyleRange includes the start and length, the
 * same instance cannot occur multiple times in the array of styles.
 * If the same style attributes, such as font and color, occur in
 * multiple StyleRanges, <code>setStyleRanges(int[], StyleRange[])</code>
 * can be used to share styles and reduce memory usage.
 * </p><p>
 * Should not be called if a LineStyleListener has been set since the
 * listener maintains the styles.
 * </p>
 *
 * @param ranges StyleRange objects containing the style information.
 * The ranges should not overlap. The style rendering is undefined if
 * the ranges do overlap. Must not be null. The styles need to be in order.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_RANGE when the last of the style ranges is outside the valid range (> getCharCount())</li>
 * </ul>
 *
 * @see #setStyleRanges(int[], StyleRange[])
 */
public void setStyleRanges(StyleRange[] ranges) {
    checkWidget();
    if (isListening(LineGetStyle)) return;
    // SWT extension: allow null for zero length string
    //if (ranges is null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
    setStyleRanges(0, 0, null, ranges, true);
}
/**
 * Sets the tab width.
 *
 * @param tabs tab width measured in characters.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setTabs(int tabs) {
    checkWidget();
    tabLength = tabs;
    renderer.setFont(null, tabs);
    resetCache(0, content.getLineCount());
    setCaretLocation();
    super.redraw();
}
/**
 * Sets the widget content.
 * If the widget has the SWT.SINGLE style and "text" contains more than
 * one line, only the first line is rendered but the text is stored
 * unchanged. A subsequent call to getText will return the same text
 * that was set.
 * <p>
 * <b>Note:</b> Only a single line of text should be set when the SWT.SINGLE
 * style is used.
 * </p>
 *
 * @param text new widget content. Replaces existing content. Line styles
 *  that were set using StyledText API are discarded.  The
 *  current selection is also discarded.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setText(String text) {
    checkWidget();
    // SWT extension: allow null for zero length string
//     if (text is null) {
//         SWT.error(SWT.ERROR_NULL_ARGUMENT);
//     }
    Event event = new Event();
    event.start = 0;
    event.end = getCharCount();
    event.text = text;
    event.doit = true;
    notifyListeners(SWT.Verify, event);
    if (event.doit) {
        StyledTextEvent styledTextEvent = null;
        if (isListening(ExtendedModify)) {
            styledTextEvent = new StyledTextEvent(content);
            styledTextEvent.start = event.start;
            styledTextEvent.end = event.start + event.text.length;
            styledTextEvent.text = content.getTextRange(event.start, event.end - event.start);
        }
        content.setText(event.text);
        sendModifyEvent(event);
        if (styledTextEvent !is null) {
            notifyListeners(ExtendedModify, styledTextEvent);
        }
    }
}
/**
 * Sets the text limit to the specified number of characters.
 * <p>
 * The text limit specifies the amount of text that
 * the user can type into the widget.
 * </p>
 *
 * @param limit the new text limit.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @exception IllegalArgumentException <ul>
 *   <li>ERROR_CANNOT_BE_ZERO when limit is 0</li>
 * </ul>
 */
public void setTextLimit(int limit) {
    checkWidget();
    if (limit is 0) {
        SWT.error(SWT.ERROR_CANNOT_BE_ZERO);
    }
    textLimit = limit;
}
/**
 * Sets the top index. Do nothing if there is no text set.
 * <p>
 * The top index is the index of the line that is currently at the top
 * of the widget. The top index changes when the widget is scrolled.
 * Indexing starts from zero.
 * Note: The top index is reset to 0 when new text is set in the widget.
 * </p>
 *
 * @param topIndex new top index. Must be between 0 and
 *  getLineCount() - fully visible lines per page. If no lines are fully
 *  visible the maximum value is getLineCount() - 1. An out of range
 *  index will be adjusted accordingly.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setTopIndex(int topIndex) {
    checkWidget();
    if (getCharCount() is 0) {
        return;
    }
    int lineCount = content.getLineCount(), pixel;
    if (isFixedLineHeight()) {
        int pageSize = Math.max(1, Math.min(lineCount, getLineCountWhole()));
        if (topIndex < 0) {
            topIndex = 0;
        } else if (topIndex > lineCount - pageSize) {
            topIndex = lineCount - pageSize;
        }
        pixel = getLinePixel(topIndex);
    } else {
        topIndex = Math.max(0, Math.min(lineCount - 1, topIndex));
        pixel = getLinePixel(topIndex);
        if (pixel > 0) {
            pixel = getAvailableHeightBellow(pixel);
        } else {
            pixel = getAvailableHeightAbove(pixel);
        }
    }
    scrollVertical(pixel, true);
}
/**
 * Sets the top pixel offset. Do nothing if there is no text set.
 * <p>
 * The top pixel offset is the vertical pixel offset of the widget. The
 * widget is scrolled so that the given pixel position is at the top.
 * The top index is adjusted to the corresponding top line.
 * Note: The top pixel is reset to 0 when new text is set in the widget.
 * </p>
 *
 * @param pixel new top pixel offset. Must be between 0 and
 *  (getLineCount() - visible lines per page) / getLineHeight()). An out
 *  of range offset will be adjusted accordingly.
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * @since 2.0
 */
public void setTopPixel(int pixel) {
    checkWidget();
    if (getCharCount() is 0) {
        return;
    }
    if (pixel < 0) pixel = 0;
    int lineCount = content.getLineCount();
    int height = clientAreaHeight - topMargin - bottomMargin;
    int verticalOffset = getVerticalScrollOffset();
    if (isFixedLineHeight()) {
        int maxTopPixel = Math.max(0, lineCount * getVerticalIncrement() - height);
        if (pixel > maxTopPixel) pixel = maxTopPixel;
        pixel -= verticalOffset;
    } else {
        pixel -= verticalOffset;
        if (pixel > 0) {
            pixel = getAvailableHeightBellow(pixel);
        }
    }
    scrollVertical(pixel, true);
}
/**
 * Sets whether the widget wraps lines.
 * <p>
 * This overrides the creation style bit SWT.WRAP.
 * </p>
 *
 * @param wrap true=widget wraps lines, false=widget does not wrap lines
 * @since 2.0
 */
public void setWordWrap(bool wrap) {
    checkWidget();
    if ((getStyle() & SWT.SINGLE) !is 0) return;
    if (wordWrap is wrap) return;
    wordWrap = wrap;
    setVariableLineHeight();
    resetCache(0, content.getLineCount());
    horizontalScrollOffset = 0;
    ScrollBar horizontalBar = getHorizontalBar();
    if (horizontalBar !is null) {
        horizontalBar.setVisible(!wordWrap);
    }
    setScrollBars(true);
    setCaretLocation();
    super.redraw();
}
// SWT: If necessary, scroll to show the location
bool showLocation(Rectangle rect, bool scrollPage) {
    int clientAreaWidth = this.clientAreaWidth - leftMargin - rightMargin;
    int clientAreaHeight = this.clientAreaHeight - topMargin - bottomMargin;
    bool scrolled = false;
    if (rect.y <= topMargin) {
        scrolled = scrollVertical(rect.y - topMargin, true);
    } else if (rect.y + rect.height > clientAreaHeight) {
        if (clientAreaHeight is 0) {
            scrolled = scrollVertical(rect.y, true);
        } else {
            scrolled = scrollVertical(rect.y + rect.height - clientAreaHeight, true);
        }
    }
    if (clientAreaWidth > 0) {
        int minScroll = scrollPage ? clientAreaWidth / 4 : 0;
        if (rect.x < leftMargin) {
            int scrollWidth = Math.max(leftMargin - rect.x, minScroll);
            int maxScroll = horizontalScrollOffset;
            scrolled = scrollHorizontal(-Math.min(maxScroll, scrollWidth), true);
        } else if (rect.x + rect.width > clientAreaWidth) {
            int scrollWidth =  Math.max(rect.x + rect.width - clientAreaWidth, minScroll);
            int maxScroll = renderer.getWidth() - horizontalScrollOffset - this.clientAreaWidth;
            scrolled = scrollHorizontal(Math.min(maxScroll, scrollWidth), true);
        }
    }
    return scrolled;
}
/**
 * Sets the caret location and scrolls the caret offset into view.
 */
void showCaret() {
    Rectangle bounds = getBoundsAtOffset(caretOffset);
    if (!showLocation(bounds, true)) {
        setCaretLocation();
    }
}
/**
 * Scrolls the selection into view.
 * <p>
 * The end of the selection will be scrolled into view.
 * Note that if a right-to-left selection exists, the end of the selection is
 * the visual beginning of the selection (i.e., where the caret is located).
 * </p>
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void showSelection() {
    checkWidget();
    // is selection from right-to-left?
    bool rightToLeft = caretOffset is selection.x;
    int startOffset, endOffset;
    if (rightToLeft) {
        startOffset = selection.y;
        endOffset = selection.x;
    } else {
        startOffset = selection.x;
        endOffset = selection.y;
    }

    Rectangle startBounds = getBoundsAtOffset(startOffset);
    Rectangle endBounds = getBoundsAtOffset(endOffset);

    // can the selection be fully displayed within the widget's visible width?
    int w = clientAreaWidth - leftMargin - rightMargin;
    bool selectionFits = rightToLeft ? startBounds.x - endBounds.x <= w : endBounds.x - startBounds.x <= w;
    if (selectionFits) {
        // show as much of the selection as possible by first showing
        // the start of the selection
        if (showLocation(startBounds, false)) {
            // endX value could change if showing startX caused a scroll to occur
            endBounds = getBoundsAtOffset(endOffset);
        }
        // the character at endOffset is not part of the selection
        endBounds.width = 0;
        showLocation(endBounds, false);
    } else {
        // just show the end of the selection since the selection start
        // will not be visible
        showLocation(endBounds, true);
    }
}
/**
 * Updates the selection and caret position depending on the text change.
 * <p>
 * If the selection intersects with the replaced text, the selection is
 * reset and the caret moved to the end of the new text.
 * If the selection is behind the replaced text it is moved so that the
 * same text remains selected.  If the selection is before the replaced text
 * it is left unchanged.
 * </p>
 *
 * @param startOffset offset of the text change
 * @param replacedLength length of text being replaced
 * @param newLength length of new text
 */
void updateSelection(int startOffset, int replacedLength, int newLength) {
    if (selection.y <= startOffset) {
        // selection ends before text change
        if (wordWrap) setCaretLocation();
        return;
    }
    if (selection.x < startOffset) {
        // clear selection fragment before text change
        internalRedrawRange(selection.x, startOffset - selection.x);
    }
    if (selection.y > startOffset + replacedLength && selection.x < startOffset + replacedLength) {
        // clear selection fragment after text change.
        // do this only when the selection is actually affected by the
        // change. Selection is only affected if it intersects the change (1GDY217).
        int netNewLength = newLength - replacedLength;
        int redrawStart = startOffset + newLength;
        internalRedrawRange(redrawStart, selection.y + netNewLength - redrawStart);
    }
    if (selection.y > startOffset && selection.x < startOffset + replacedLength) {
        // selection intersects replaced text. set caret behind text change
        setSelection(startOffset + newLength, 0, true);
    } else {
        // move selection to keep same text selected
        setSelection(selection.x + newLength - replacedLength, selection.y - selection.x, true);
    }
    setCaretLocation();
}
}