org.eclipse.swt.dnd.TreeDragSourceEffect Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2007, 2012 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.graphics.*;
import org.eclipse.swt.internal.cocoa.*;
import org.eclipse.swt.widgets.*;
/**
* This class provides default implementations to display a source image
* when a drag is initiated from a Tree
.
*
* Classes that wish to provide their own source image for a Tree
can
* extend TreeDragSourceEffect
class and override the TreeDragSourceEffect.dragStart
* method and set the field DragSourceEvent.image
with their own image.
*
* Subclasses that override any methods of this class must call the corresponding
* super
method to get the default drag under effect implementation.
*
* @see DragSourceEffect
* @see DragSourceEvent
* @see Sample code and further information
*
* @since 3.3
*/
public class TreeDragSourceEffect extends DragSourceEffect {
Image dragSourceImage = null;
/**
* Creates a new TreeDragSourceEffect
to handle drag effect
* from the specified Tree
.
*
* @param tree the Tree
that the user clicks on to initiate the drag
*/
public TreeDragSourceEffect(Tree tree) {
super(tree);
}
/**
* This implementation of dragFinished
disposes the image
* that was created in TreeDragSourceEffect.dragStart
.
*
* Subclasses that override this method should call super.dragFinished(event)
* to dispose the image in the default implementation.
*
* @param event the information associated with the drag finished event
*/
@Override
public void dragFinished(DragSourceEvent event) {
if (dragSourceImage != null) dragSourceImage.dispose();
dragSourceImage = null;
}
/**
* This implementation of dragStart
will create a default
* image that will be used during the drag. The image should be disposed
* when the drag is completed in the TreeDragSourceEffect.dragFinished
* method.
*
* Subclasses that override this method should call super.dragStart(event)
* to use the image from the default implementation.
*
* @param event the information associated with the drag start event
*/
@Override
public void dragStart(DragSourceEvent event) {
event.image = getDragSourceImage(event);
}
Image getDragSourceImage(DragSourceEvent event) {
if (dragSourceImage != null) dragSourceImage.dispose();
dragSourceImage = null;
NSPoint point = new NSPoint();
long /*int*/ ptr = OS.malloc(NSPoint.sizeof);
OS.memmove(ptr, point, NSPoint.sizeof);
NSEvent nsEvent = NSApplication.sharedApplication().currentEvent();
NSTableView widget = (NSTableView)control.view;
NSImage nsImage = widget.dragImageForRowsWithIndexes(widget.selectedRowIndexes(), widget.tableColumns(), nsEvent, ptr);
OS.memmove(point, ptr, NSPoint.sizeof);
OS.free(ptr);
//TODO: Image representation wrong???
Image image = Image.cocoa_new(control.getDisplay(), SWT.BITMAP, nsImage);
dragSourceImage = image;
nsImage.retain();
event.offsetX = (int)point.x;
event.offsetY = (int)point.y;
return image;
}
}