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/*******************************************************************************
* 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
*******************************************************************************/
package org.eclipse.swt.dnd;
import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
/**
* This class provides a default drag under effect (eg. select, insert, scroll and expand)
* when a drag occurs over a <code>Tree</code>.
*
* <p>Classes that wish to provide their own drag under effect for a <code>Tree</code>
* can extend the <code>TreeDropTargetEffect</code> class and override any applicable methods
* in <code>TreeDropTargetEffect</code> to display their own drag under effect.</p>
*
* Subclasses that override any methods of this class must 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_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL</dd>
* </dl>
* </p><p>
* Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or
* FEEDBACK_INSERT_AFTER may be specified.
* </p>
*
* @see DropTargetAdapter
* @see DropTargetEvent
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*
* @since 3.3
*/
public class TreeDropTargetEffect extends DropTargetEffect {
static final int SCROLL_HYSTERESIS = 150; // milli seconds
static final int EXPAND_HYSTERESIS = 1000; // milli seconds
int currentEffect = DND.FEEDBACK_NONE;
TreeItem currentItem;
PaintListener paintListener;
TreeItem dropSelection = null;
TreeItem insertItem = null;
boolean insertBefore = false;
TreeItem scrollItem;
long scrollBeginTime;
TreeItem expandItem;
long expandBeginTime;
/**
* Creates a new <code>TreeDropTargetEffect</code> to handle the drag under effect on the specified
* <code>Tree</code>.
*
* @param tree the <code>Tree</code> over which the user positions the cursor to drop the data
*/
public TreeDropTargetEffect(Tree tree) {
super(tree);
}
int checkEffect(int effect) {
// Some effects are mutually exclusive. Make sure that only one of the mutually exclusive effects has been specified.
if ((effect & DND.FEEDBACK_SELECT) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
return effect;
}
/**
* 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 enter event
*
* @see DropTargetAdapter
* @see DropTargetEvent
*/
public void dragEnter(DropTargetEvent event) {
insertItem = null;
currentItem = null;
dropSelection = null;
expandBeginTime = 0;
expandItem = null;
scrollBeginTime = 0;
scrollItem = null;
}
/**
* 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) {
Tree tree = (Tree) control;
if (insertItem != null) {
tree.setInsertMark(null, false);
insertItem = null;
}
if (currentItem != null) {
setDropSelection(tree, null);
currentItem = null;
}
expandBeginTime = 0;
expandItem = null;
scrollBeginTime = 0;
scrollItem = null;
}
/**
* 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_INSERT_BEFORE
* @see DND#FEEDBACK_INSERT_AFTER
* @see DND#FEEDBACK_SCROLL
*/
public void dragOver(DropTargetEvent event) {
Tree tree = (Tree) control;
int effect = checkEffect(event.feedback);
TreeItem item = (TreeItem)getItem(tree, event.x, event.y);
if ((effect & DND.FEEDBACK_EXPAND) == 0) {
expandBeginTime = 0;
expandItem = null;
} else {
if (item != null && item.equals(expandItem) && expandBeginTime != 0) {
if (System.currentTimeMillis() >= expandBeginTime) {
if (item.getItemCount() > 0 && !item.getExpanded()) {
Event e = new Event();
e.x = event.x;
e.y = event.y;
e.item = item;
e.time = (int) System.currentTimeMillis();
tree.notifyListeners(SWT.Expand, e);
if (item.isDisposed()) return;
item.setExpanded(true);
}
expandBeginTime = 0;
expandItem = null;
}
} else {
expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS;
expandItem = item;
}
}
if ((effect & DND.FEEDBACK_SCROLL) == 0) {
scrollBeginTime = 0;
scrollItem = null;
} else {
if (item != null && item.equals(scrollItem) && scrollBeginTime != 0) {
if (System.currentTimeMillis() >= scrollBeginTime) {
Rectangle area = tree.getClientArea();
int headerHeight = tree.getHeaderHeight();
int itemHeight= tree.getItemHeight();
Point pt = new Point(event.x, event.y);
pt = tree.getDisplay().map(null, tree, pt);
TreeItem nextItem = null;
if (pt.y < area.y + headerHeight + 2 * itemHeight) {
nextItem = previousItem(tree, item);
}
if (pt.y > area.y + area.height - 2 * itemHeight) {
nextItem = nextItem(tree, item);
}
if (nextItem != null) tree.showItem(nextItem);
scrollBeginTime = 0;
scrollItem = null;
}
} else {
scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
scrollItem = item;
}
}
if ((effect & DND.FEEDBACK_SELECT) != 0) {
if (currentItem != item || (currentEffect & DND.FEEDBACK_SELECT) == 0) {
setDropSelection(tree, item);
currentEffect = effect;
currentItem = item;
}
} else {
setDropSelection(tree, null);
}
if ((effect & DND.FEEDBACK_INSERT_AFTER) != 0 ||
(effect & DND.FEEDBACK_INSERT_BEFORE) != 0) {
if (currentItem != item ||
((effect & DND.FEEDBACK_INSERT_AFTER) != (currentEffect & DND.FEEDBACK_INSERT_AFTER)) ||
((effect & DND.FEEDBACK_INSERT_BEFORE) != (currentEffect & DND.FEEDBACK_INSERT_BEFORE))) {
setInsertMark(tree, item, (effect & DND.FEEDBACK_INSERT_BEFORE) != 0);
currentEffect = effect;
currentItem = item;
}
} else {
setInsertMark(tree, null, false);
}
}
void setDropSelection (Tree tree, TreeItem item) {
if (item == dropSelection) return;
if (dropSelection != null && !dropSelection.isDisposed()) {
Rectangle bounds = dropSelection.getBounds();
tree.redraw(bounds.x, bounds.y, bounds.width, bounds.height, true);
}
dropSelection = item;
if (dropSelection != null && !dropSelection.isDisposed()) {
Rectangle bounds = dropSelection.getBounds();
tree.redraw(bounds.x, bounds.y, bounds.width, bounds.height, true);
}
if (dropSelection == null) {
if (paintListener != null) {
tree.removePaintListener(paintListener);
paintListener = null;
}
} else {
if (paintListener == null) {
paintListener = new PaintListener() {
public void paintControl(PaintEvent e) {
if (dropSelection == null || dropSelection.isDisposed()) return;
GC gc = e.gc;
boolean xor = gc.getXORMode();
gc.setXORMode(true);
Rectangle bounds = dropSelection.getBounds();
gc.fillRectangle(bounds.x, bounds.y, bounds.width, bounds.height);
gc.setXORMode(xor);
}
};
tree.addPaintListener(paintListener);
}
}
}
void setInsertMark(Tree tree, TreeItem item, boolean before) {
if (item == insertItem && before == insertBefore) return;
insertItem = item;
insertBefore = before;
tree.setInsertMark(item, before);
}
}
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