--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/dnd/DropTargetEffect.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,169 @@
+/*******************************************************************************
+ * Copyright (c) 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.dnd;
+
+import dwt.*;
+import dwt.graphics.*;
+import dwt.widgets.*;
+
+
+/**
+ * This class provides a default drag under effect during a drag and drop. 
+ * The current implementation does not provide any visual feedback.
+ * 
+ * <p>The drop target effect has the same API as the 
+ * <code>DropTargetAdapter</code> so that it can provide custom visual 
+ * feedback when a <code>DropTargetEvent</code> occurs. 
+ * </p>
+ * 
+ * <p>Classes that wish to provide their own drag under effect
+ * can extend the <code>DropTargetEffect</code> and override any applicable methods 
+ * in <code>DropTargetAdapter</code> to display their own drag under effect.</p>
+ *
+ * <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_EXPAND, FEEDBACK_INSERT_AFTER, FEEDBACK_INSERT_BEFORE, 
+ * FEEDBACK_NONE, FEEDBACK_SELECT, FEEDBACK_SCROLL</dd>
+ * </dl>
+ * </p>
+ * 
+ * @see DropTargetAdapter
+ * @see DropTargetEvent
+ * 
+ * @since 3.3
+ */
+public class DropTargetEffect : DropTargetAdapter {
+    Control control;
+
+    /**
+     * Creates a new <code>DropTargetEffect</code> to handle the drag under effect on the specified 
+     * <code>Control</code>.
+     * 
+     * @param control the <code>Control</code> over which the user positions the cursor to drop the data
+     * 
+     * @exception IllegalArgumentException <ul>
+     *    <li>ERROR_NULL_ARGUMENT - if the control is null</li>
+     * </ul>
+     */
+    public DropTargetEffect(Control control) {
+        if (control is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
+        this.control = control;
+    }
+
+    /**
+     * Returns the Control which is registered for this DropTargetEffect.  This is the control over which the 
+     * user positions the cursor to drop the data.
+     *
+     * @return the Control which is registered for this DropTargetEffect
+     */
+    public Control getControl() {
+        return control;
+    }
+    
+    /**
+     * Returns the item at the given x-y coordinate in the receiver
+     * or null if no such item exists. The x-y coordinate is in the
+     * display relative coordinates.
+     *
+     * @param x the x coordinate used to locate the item
+     * @param y the y coordinate used to locate the item
+     * @return the item at the given x-y coordinate, or null if the coordinate is not in a selectable item
+     */
+    public Widget getItem(int x, int y) {
+        if (control instanceof Table) {
+            return getItem((Table) control, x, y);
+        }
+        if (control instanceof Tree) {
+            return getItem((Tree) control, x, y);
+        }           
+        return null;
+    }
+    
+    Widget getItem(Table table, int x, int y) {
+        Point coordinates = new Point(x, y);
+        coordinates = table.toControl(coordinates);
+        TableItem item = table.getItem(coordinates);
+        if (item !is null) return item;
+        Rectangle area = table.getClientArea();
+        int tableBottom = area.y + area.height;
+        int itemCount = table.getItemCount();
+        for (int i=table.getTopIndex(); i<itemCount; i++) {
+            item = table.getItem(i);
+            Rectangle rect = item.getBounds();
+            rect.x = area.x;
+            rect.width = area.width;
+            if (rect.contains(coordinates)) return item;
+            if (rect.y > tableBottom) break;
+        }
+        return null;
+    }
+    
+    Widget getItem(Tree tree, int x, int y) {
+        Point point = new Point(x, y);
+        point = tree.toControl(point);
+        TreeItem item = tree.getItem(point);
+        if (item is null) {
+            Rectangle area = tree.getClientArea();
+            if (area.contains(point)) {
+                int treeBottom = area.y + area.height;
+                item = tree.getTopItem();
+                while (item !is null) {
+                    Rectangle rect = item.getBounds();
+                    int itemBottom = rect.y + rect.height;
+                    if (rect.y <= point.y && point.y < itemBottom) return item;
+                    if (itemBottom > treeBottom) break;
+                    item = nextItem(tree, item);
+                }
+                return null;
+            }
+        }
+        return item;
+    }
+    
+    TreeItem nextItem(Tree tree, TreeItem item) {
+        if (item is null) return null;
+        if (item.getExpanded() && item.getItemCount() > 0) return item.getItem(0);
+        TreeItem childItem = item;
+        TreeItem parentItem = childItem.getParentItem();
+        int index = parentItem is null ? tree.indexOf(childItem) : parentItem.indexOf(childItem);
+        int count = parentItem is null ? tree.getItemCount() : parentItem.getItemCount();
+        while (true) {
+            if (index + 1 < count) return parentItem is null ? tree.getItem(index + 1) : parentItem.getItem(index + 1);
+            if (parentItem is null) return null;
+            childItem = parentItem;
+            parentItem = childItem.getParentItem();
+            index = parentItem is null ? tree.indexOf(childItem) : parentItem.indexOf(childItem);
+            count = parentItem is null ? tree.getItemCount() : parentItem.getItemCount();
+        }
+    }
+    
+    TreeItem previousItem(Tree tree, TreeItem item) {
+        if (item is null) return null;
+        TreeItem childItem = item;
+        TreeItem parentItem = childItem.getParentItem();
+        int index = parentItem is null ? tree.indexOf(childItem) : parentItem.indexOf(childItem);
+        if (index is 0) return parentItem;
+        TreeItem nextItem = parentItem is null ? tree.getItem(index-1) : parentItem.getItem(index-1);
+        int count = nextItem.getItemCount();
+        while (count > 0 && nextItem.getExpanded()) {
+            nextItem = nextItem.getItem(count - 1);
+            count = nextItem.getItemCount();
+        }
+        return nextItem;
+    }
+}