--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/jface/text/WhitespaceCharacterPainter.d	Sat Aug 23 19:10:48 2008 +0200
@@ -0,0 +1,380 @@
+/*******************************************************************************
+ * Copyright (c) 2006, 2007 Wind River Systems, Inc. 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:
+ *     Anton Leherbauer (Wind River Systems) - initial API and implementation - https://bugs.eclipse.org/bugs/show_bug.cgi?id=22712
+ *     Anton Leherbauer (Wind River Systems) - [painting] Long lines take too long to display when "Show Whitespace Characters" is enabled - https://bugs.eclipse.org/bugs/show_bug.cgi?id=196116
+ *     Anton Leherbauer (Wind River Systems) - [painting] Whitespace characters not drawn when scrolling to right slowly - https://bugs.eclipse.org/bugs/show_bug.cgi?id=206633
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.jface.text.WhitespaceCharacterPainter;
+
+import dwt.dwthelper.utils;
+
+import dwt.custom.StyleRange;
+import dwt.custom.StyledText;
+import dwt.custom.StyledTextContent;
+import dwt.events.PaintEvent;
+import dwt.events.PaintListener;
+import dwt.graphics.Color;
+import dwt.graphics.FontMetrics;
+import dwt.graphics.GC;
+import dwt.graphics.Point;
+
+
+/**
+ * A painter for drawing visible characters for (invisible) whitespace 
+ * characters.
+ * 
+ * @since 3.3
+ */
+public class WhitespaceCharacterPainter : IPainter, PaintListener {
+
+    private static final char SPACE_SIGN= '\u00b7';
+    private static final char IDEOGRAPHIC_SPACE_SIGN= '\u00b0';
+    private static final char TAB_SIGN= '\u00bb';
+    private static final char CARRIAGE_RETURN_SIGN= '\u00a4';
+    private static final char LINE_FEED_SIGN= '\u00b6';
+    
+    /** Indicates whether this painter is active. */
+    private bool fIsActive= false;
+    /** The source viewer this painter is attached to. */
+    private ITextViewer fTextViewer;
+    /** The viewer's widget. */
+    private StyledText fTextWidget;
+    /** Tells whether the advanced graphics sub system is available. */
+    private bool fIsAdvancedGraphicsPresent;
+
+    /**
+     * Creates a new painter for the given text viewer.
+     * 
+     * @param textViewer  the text viewer the painter should be attached to
+     */
+    public WhitespaceCharacterPainter(ITextViewer textViewer) {
+        super();
+        fTextViewer= textViewer;
+        fTextWidget= textViewer.getTextWidget();
+        GC gc= new GC(fTextWidget);
+        gc.setAdvanced(true);
+        fIsAdvancedGraphicsPresent= gc.getAdvanced();
+        gc.dispose();
+    }
+
+    /*
+     * @see dwtx.jface.text.IPainter#dispose()
+     */
+    public void dispose() {
+        fTextViewer= null;
+        fTextWidget= null;
+    }
+
+    /*
+     * @see dwtx.jface.text.IPainter#paint(int)
+     */
+    public void paint(int reason) {
+        IDocument document= fTextViewer.getDocument();
+        if (document is null) {
+            deactivate(false);
+            return;
+        }
+        if (!fIsActive) {
+            fIsActive= true;
+            fTextWidget.addPaintListener(this);
+            redrawAll();
+        } else if (reason is CONFIGURATION || reason is INTERNAL) {
+            redrawAll();
+        } else if (reason is TEXT_CHANGE) {
+            // redraw current line only
+            try {
+                IRegion lineRegion =
+                    document.getLineInformationOfOffset(getDocumentOffset(fTextWidget.getCaretOffset()));
+                int widgetOffset= getWidgetOffset(lineRegion.getOffset());
+                int charCount= fTextWidget.getCharCount();
+                int redrawLength= Math.min(lineRegion.getLength(), charCount - widgetOffset);
+                if (widgetOffset >= 0 && redrawLength > 0) {
+                    fTextWidget.redrawRange(widgetOffset, redrawLength, true);
+                }
+            } catch (BadLocationException e) {
+                // ignore
+            }
+        }
+    }
+
+    /*
+     * @see dwtx.jface.text.IPainter#deactivate(bool)
+     */
+    public void deactivate(bool redraw) {
+        if (fIsActive) {
+            fIsActive= false;
+            fTextWidget.removePaintListener(this);
+            if (redraw) {
+                redrawAll();
+            }
+        }
+    }
+
+    /*
+     * @see dwtx.jface.text.IPainter#setPositionManager(dwtx.jface.text.IPaintPositionManager)
+     */
+    public void setPositionManager(IPaintPositionManager manager) {
+        // no need for a position manager
+    }
+
+    /*
+     * @see dwt.events.PaintListener#paintControl(dwt.events.PaintEvent)
+     */
+    public void paintControl(PaintEvent event) {
+        if (fTextWidget !is null) {
+            handleDrawRequest(event.gc, event.x, event.y, event.width, event.height);
+        }
+    }
+
+    /**
+     * Draw characters in view range.
+     * 
+     * @param gc
+     * @param x
+     * @param y
+     * @param w
+     * @param h
+     */
+    private void handleDrawRequest(GC gc, int x, int y, int w, int h) {
+        int startLine= fTextWidget.getLineIndex(y);
+        int endLine= fTextWidget.getLineIndex(y + h - 1);
+        if (startLine <= endLine && startLine < fTextWidget.getLineCount()) {
+            if (fIsAdvancedGraphicsPresent) {
+                int alpha= gc.getAlpha();
+                gc.setAlpha(100);
+                drawLineRange(gc, startLine, endLine, x, w);
+                gc.setAlpha(alpha);
+            } else
+                drawLineRange(gc, startLine, endLine, x, w);
+        }
+    }
+
+    /**
+     * Draw the given line range.
+     * 
+     * @param gc
+     * @param startLine  first line number
+     * @param endLine  last line number (inclusive)
+     * @param x  the X-coordinate of the drawing range
+     * @param w  the width of the drawing range
+     */
+    private void drawLineRange(GC gc, int startLine, int endLine, int x, int w) {
+        final int viewPortWidth= fTextWidget.getClientArea().width;
+        for (int line= startLine; line <= endLine; line++) {
+            int lineOffset= fTextWidget.getOffsetAtLine(line);
+            // line end offset including line delimiter
+            int lineEndOffset;
+            if (line < fTextWidget.getLineCount() - 1) {
+                lineEndOffset= fTextWidget.getOffsetAtLine(line + 1);
+            } else {
+                lineEndOffset= fTextWidget.getCharCount();
+            }
+            // line length excluding line delimiter
+            int lineLength= lineEndOffset - lineOffset;
+            while (lineLength > 0) {
+                char c= fTextWidget.getTextRange(lineOffset + lineLength - 1, 1).charAt(0);
+                if (c !is '\r' && c !is '\n') {
+                    break;
+                }
+                --lineLength;
+            }
+            // compute coordinates of last character on line
+            Point endOfLine= fTextWidget.getLocationAtOffset(lineOffset + lineLength);
+            if (x - endOfLine.x > viewPortWidth) {
+                // line is not visible
+                continue;
+            }
+            // Y-coordinate of line
+            int y= fTextWidget.getLinePixel(line);
+            // compute first visible char offset
+            int startOffset;
+            try {
+                startOffset= fTextWidget.getOffsetAtLocation(new Point(x, y)) - 1;
+                if (startOffset - 2 <= lineOffset) {
+                    startOffset= lineOffset;
+                }
+            } catch (IllegalArgumentException iae) {
+                startOffset= lineOffset;
+            }
+            // compute last visible char offset
+            int endOffset;
+            if (x + w >= endOfLine.x) {
+                // line end is visible
+                endOffset= lineEndOffset;
+            } else {
+                try {
+                    endOffset= fTextWidget.getOffsetAtLocation(new Point(x + w - 1, y)) + 1;
+                    if (endOffset + 2 >= lineEndOffset) {
+                        endOffset= lineEndOffset;
+                    }
+                } catch (IllegalArgumentException iae) {
+                    endOffset= lineEndOffset;
+                }
+            }
+            // draw character range
+            if (endOffset > startOffset) {
+                drawCharRange(gc, startOffset, endOffset);
+            }
+        }
+    }
+
+    /**
+     * Draw characters of content range.
+     * 
+     * @param gc the GC
+     * @param startOffset inclusive start index
+     * @param endOffset exclusive end index
+     */
+    private void drawCharRange(GC gc, int startOffset, int endOffset) {
+        StyledTextContent content= fTextWidget.getContent();
+        int length= endOffset - startOffset;
+        String text= content.getTextRange(startOffset, length);
+        StyleRange styleRange= null;
+        Color fg= null;
+        Point selection= fTextWidget.getSelection();
+        StringBuffer visibleChar= new StringBuffer(10);
+        for (int textOffset= 0; textOffset <= length; ++textOffset) {
+            int delta= 0;
+            bool eol= false;
+            if (textOffset < length) {
+                delta= 1;
+                char c= text.charAt(textOffset);
+                switch (c) {
+                case ' ' :
+                    visibleChar.append(SPACE_SIGN);
+                    // 'continue' would improve performance but may produce drawing errors
+                    // for long runs of space if width of space and dot differ
+                    break;
+                case '\u3000' : // ideographic whitespace
+                    visibleChar.append(IDEOGRAPHIC_SPACE_SIGN);
+                    // 'continue' would improve performance but may produce drawing errors
+                    // for long runs of space if width of space and dot differ
+                    break;
+                case '\t' :
+                    visibleChar.append(TAB_SIGN);
+                    break;
+                case '\r' :
+                    visibleChar.append(CARRIAGE_RETURN_SIGN);
+                    if (textOffset >= length - 1 || text.charAt(textOffset + 1) !is '\n') {
+                        eol= true;
+                        break;
+                    }
+                    continue;
+                case '\n' :
+                    visibleChar.append(LINE_FEED_SIGN);
+                    eol= true;
+                    break;
+                default :
+                    delta= 0;
+                    break;
+                }
+            }
+            if (visibleChar.length() > 0) {
+                int widgetOffset= startOffset + textOffset - visibleChar.length() + delta;
+                if (!eol || !isFoldedLine(content.getLineAtOffset(widgetOffset))) {
+                    if (widgetOffset >= selection.x && widgetOffset < selection.y) {
+                        fg= fTextWidget.getSelectionForeground();
+                    } else if (styleRange is null || styleRange.start + styleRange.length <= widgetOffset) {
+                        styleRange= fTextWidget.getStyleRangeAtOffset(widgetOffset);
+                        if (styleRange is null || styleRange.foreground is null) {
+                            fg= fTextWidget.getForeground();
+                        } else {
+                            fg= styleRange.foreground;
+                        }
+                    }
+                    draw(gc, widgetOffset, visibleChar.toString(), fg);
+                }
+                visibleChar.delete(0, visibleChar.length());
+            }
+        }
+    }
+
+    /**
+     * Check if the given widget line is a folded line.
+     * 
+     * @param widgetLine  the widget line number
+     * @return <code>true</code> if the line is folded
+     */
+    private bool isFoldedLine(int widgetLine) {
+        if (fTextViewer instanceof ITextViewerExtension5) {
+            ITextViewerExtension5 extension= (ITextViewerExtension5)fTextViewer;
+            int modelLine= extension.widgetLine2ModelLine(widgetLine);
+            int widgetLine2= extension.modelLine2WidgetLine(modelLine + 1);
+            return widgetLine2 is -1;
+        }
+        return false;
+    }
+
+    /**
+     * Redraw all of the text widgets visible content.
+     */
+    private void redrawAll() {
+        fTextWidget.redraw();
+    }
+
+    /**
+     * Draw string at widget offset.
+     * 
+     * @param gc
+     * @param offset the widget offset
+     * @param s the string to be drawn
+     * @param fg the foreground color
+     */
+    private void draw(GC gc, int offset, String s, Color fg) {
+        // Compute baseline delta (see https://bugs.eclipse.org/bugs/show_bug.cgi?id=165640)
+        int baseline= fTextWidget.getBaseline(offset);
+        FontMetrics fontMetrics= gc.getFontMetrics();
+        int fontBaseline= fontMetrics.getAscent() + fontMetrics.getLeading();
+        int baslineDelta= baseline - fontBaseline;
+        
+        Point pos= fTextWidget.getLocationAtOffset(offset);
+        gc.setForeground(fg);
+        gc.drawString(s, pos.x, pos.y + baslineDelta, true);
+    }
+
+    /**
+     * Convert a document offset to the corresponding widget offset.
+     * 
+     * @param documentOffset
+     * @return widget offset
+     */
+    private int getWidgetOffset(int documentOffset) {
+        if (fTextViewer instanceof ITextViewerExtension5) {
+            ITextViewerExtension5 extension= (ITextViewerExtension5)fTextViewer;
+            return extension.modelOffset2WidgetOffset(documentOffset);
+        }
+        IRegion visible= fTextViewer.getVisibleRegion();
+        int widgetOffset= documentOffset - visible.getOffset();
+        if (widgetOffset > visible.getLength()) {
+            return -1;
+        }
+        return widgetOffset;
+    }
+
+    /**
+     * Convert a widget offset to the corresponding document offset.
+     * 
+     * @param widgetOffset
+     * @return document offset
+     */
+    private int getDocumentOffset(int widgetOffset) {
+        if (fTextViewer instanceof ITextViewerExtension5) {
+            ITextViewerExtension5 extension= (ITextViewerExtension5)fTextViewer;
+            return extension.widgetOffset2ModelOffset(widgetOffset);
+        }
+        IRegion visible= fTextViewer.getVisibleRegion();
+        if (widgetOffset > visible.getLength()) {
+            return -1;
+        }
+        return widgetOffset + visible.getOffset();
+    }
+
+}