--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/custom/StyledTextDropTargetEffect.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,241 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2007 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
+ *******************************************************************************/
+module dwt.custom;
+
+import dwt.*;
+import dwt.dnd.*;
+import dwt.graphics.*;
+import dwt.widgets.*;
+
+/**
+ * This adapter class provides a default drag under effect (eg. select and scroll) 
+ * when a drag occurs over a <code>StyledText</code>.
+ * 
+ * <p>Classes that wish to provide their own drag under effect for a <code>StyledText</code>
+ * can extend this class, override the <code>StyledTextDropTargetEffect.dragOver</code>
+ * method and override any other applicable methods in <code>StyledTextDropTargetEffect</code> to 
+ * display their own drag under effect.</p>
+ *
+ * Subclasses that override any methods of this class should call the corresponding
+ * <code>super</code> method to get the default drag under effect implementation.
+ *
+ * <p>The feedback value is either one of the FEEDBACK constants defined in 
+ * class <code>DND</code> which is applicable to instances of this class, 
+ * or it must be built by <em>bitwise OR</em>'ing together 
+ * (that is, using the <code>int</code> "|" operator) two or more
+ * of those <code>DND</code> effect constants. 
+ * </p>
+ * <p>
+ * <dl>
+ * <dt><b>Feedback:</b></dt>
+ * <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd>
+ * </dl>
+ * </p>
+ * 
+ * @see DropTargetAdapter
+ * @see DropTargetEvent
+ * 
+ * @since 3.3
+ */
+public class StyledTextDropTargetEffect : DropTargetEffect {
+    static final int CARET_WIDTH = 2;
+    static final int SCROLL_HYSTERESIS = 100; // milli seconds
+    static final int SCROLL_TOLERANCE = 20; // pixels
+    
+    int currentOffset = -1;
+    long scrollBeginTime;
+    int scrollX = -1, scrollY = -1;
+    Listener paintListener;
+    
+    /**
+     * Creates a new <code>StyledTextDropTargetEffect</code> to handle the drag under effect on the specified 
+     * <code>StyledText</code>.
+     * 
+     * @param styledText the <code>StyledText</code> over which the user positions the cursor to drop the data
+     */
+    public StyledTextDropTargetEffect(StyledText styledText) {
+        super(styledText);
+        paintListener = new Listener () {
+            public void handleEvent (Event event) {
+                if (currentOffset !is -1) {
+                    StyledText text = (StyledText) getControl();
+                    Point position = text.getLocationAtOffset(currentOffset);
+                    int height = text.getLineHeight(currentOffset);
+                    event.gc.setBackground(event.display.getSystemColor (DWT.COLOR_BLACK));
+                    event.gc.fillRectangle(position.x, position.y, CARET_WIDTH, height);
+                }
+            }
+        };
+    }
+    
+    /**
+     * This implementation of <code>dragEnter</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragEnter</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragEnter(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag start event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     */
+    public void dragEnter(DropTargetEvent event) {
+        currentOffset = -1;
+        scrollBeginTime = 0;
+        scrollX = -1;
+        scrollY = -1;
+        getControl().removeListener(DWT.Paint, paintListener);
+        getControl().addListener (DWT.Paint, paintListener);
+    }
+    
+    /**
+     * This implementation of <code>dragLeave</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragLeave</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragLeave(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag leave event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     */
+    public void dragLeave(DropTargetEvent event) {
+        StyledText text = (StyledText) getControl();
+        if (currentOffset !is -1) {
+            refreshCaret(text, currentOffset, -1);
+        }
+        text.removeListener(DWT.Paint, paintListener);
+        scrollBeginTime = 0;
+        scrollX = -1;
+        scrollY = -1;
+    }
+
+    /**
+     * This implementation of <code>dragOver</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragOver</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragOver(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag over event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     * @see DND#FEEDBACK_SELECT
+     * @see DND#FEEDBACK_SCROLL
+     */
+    public void dragOver(DropTargetEvent event) {
+        int effect = event.feedback;
+        StyledText text = (StyledText) getControl();
+        
+        Point pt = text.getDisplay().map(null, text, event.x, event.y);
+        if ((effect & DND.FEEDBACK_SCROLL) is 0) {
+            scrollBeginTime = 0;
+            scrollX = scrollY = -1;
+        } else {
+            if (text.getCharCount() is 0) {
+                scrollBeginTime = 0;
+                scrollX = scrollY = -1;
+            } else {
+                if (scrollX !is -1 && scrollY !is -1 && scrollBeginTime !is 0 &&
+                    (pt.x >= scrollX && pt.x <= (scrollX + SCROLL_TOLERANCE) ||
+                     pt.y >= scrollY && pt.y <= (scrollY + SCROLL_TOLERANCE))) {
+                    if (System.currentTimeMillis() >= scrollBeginTime) {
+                        Rectangle area = text.getClientArea();
+                        GC gc = new GC(text);
+                        FontMetrics fm = gc.getFontMetrics();
+                        gc.dispose();
+                        int charWidth = fm.getAverageCharWidth();
+                        int scrollAmount = 10*charWidth;
+                        if (pt.x < area.x + 3*charWidth) {
+                            int leftPixel = text.getHorizontalPixel();
+                            text.setHorizontalPixel(leftPixel - scrollAmount);
+                        }
+                        if (pt.x > area.width - 3*charWidth) {
+                            int leftPixel = text.getHorizontalPixel();
+                            text.setHorizontalPixel(leftPixel + scrollAmount);
+                        }
+                        int lineHeight = text.getLineHeight();
+                        if (pt.y < area.y + lineHeight) {
+                            int topPixel = text.getTopPixel();
+                            text.setTopPixel(topPixel - lineHeight);
+                        }
+                        if (pt.y > area.height - lineHeight) {
+                            int topPixel = text.getTopPixel();
+                            text.setTopPixel(topPixel + lineHeight);
+                        }
+                        scrollBeginTime = 0;
+                        scrollX = scrollY = -1;
+                    }
+                } else {
+                    scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
+                    scrollX = pt.x;
+                    scrollY = pt.y;
+                }
+            }
+        }
+            
+        if ((effect & DND.FEEDBACK_SELECT) !is 0) {
+            int[] trailing = new int [1];
+            int newOffset = text.getOffsetAtPoint(pt.x, pt.y, trailing, false);
+            newOffset += trailing [0];
+            if (newOffset !is currentOffset) {
+                refreshCaret(text, currentOffset, newOffset);
+                currentOffset = newOffset;
+            }
+        }
+    }
+
+    void refreshCaret(StyledText text, int oldOffset, int newOffset) {
+        if (oldOffset !is newOffset) {
+            if (oldOffset !is -1) {
+                Point oldPos = text.getLocationAtOffset(oldOffset);
+                int oldHeight = text.getLineHeight(oldOffset);
+                text.redraw (oldPos.x, oldPos.y, CARET_WIDTH, oldHeight, false);
+            }
+            if (newOffset !is -1) {
+                Point newPos = text.getLocationAtOffset(newOffset);
+                int newHeight = text.getLineHeight(newOffset);
+                text.redraw (newPos.x, newPos.y, CARET_WIDTH, newHeight, false);
+            }
+        }
+    }
+
+    /**
+     * This implementation of <code>dropAccept</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dropAccept</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dropAccept(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drop accept event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     */
+    public void dropAccept(DropTargetEvent event) {
+        if (currentOffset !is -1) {
+            StyledText text = (StyledText) getControl();
+            text.setSelection(currentOffset);
+            currentOffset = -1;
+        }
+    }
+}