ResizableEditPolicy.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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.gef.editpolicies;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.draw2d.PositionConstants;

import org.eclipse.gef.GraphicalEditPart;
import org.eclipse.gef.Request;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.handles.NonResizableHandleKit;
import org.eclipse.gef.handles.ResizableHandleKit;
import org.eclipse.gef.requests.ChangeBoundsRequest;

/**
 * Provides support for selecting, positioning, and resizing an editpart.  Selection is
 * indicated via eight square handles along the editpart's figure, and a rectangular
 * handle that outlines the editpart with a 1-pixel black line. The eight square handles
 * will resize the current selection in the eight primary directions. The rectangular
 * handle will drag the current selection using a {@link
 * org.eclipse.gef.tools.DragEditPartsTracker}.
 * <P>
 * During feedback, a rectangle filled using XOR and outlined with dashes is drawn. 
 * Subclasses may tailor the feedback.
 * 
 * @author hudsonr
 */
public class ResizableEditPolicy
	extends NonResizableEditPolicy
{

private int directions = -1;
	
/**
 * @see org.eclipse.gef.editpolicies.SelectionHandlesEditPolicy#createSelectionHandles()
 */
protected List createSelectionHandles() {
	List list = new ArrayList();
	
	if (directions == 0)
		NonResizableHandleKit.addHandles((GraphicalEditPart)getHost(), list);
	else if (directions != -1) {
		ResizableHandleKit.addMoveHandle((GraphicalEditPart)getHost(), list);
		if ((directions & PositionConstants.EAST) != 0)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.EAST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.EAST);
		if ((directions & PositionConstants.SOUTH_EAST) == PositionConstants.SOUTH_EAST)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.SOUTH_EAST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list,
					PositionConstants.SOUTH_EAST);
		if ((directions & PositionConstants.SOUTH) != 0)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.SOUTH);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.SOUTH);
		if ((directions & PositionConstants.SOUTH_WEST) == PositionConstants.SOUTH_WEST)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.SOUTH_WEST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
						PositionConstants.SOUTH_WEST);
		if ((directions & PositionConstants.WEST) != 0)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.WEST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
						PositionConstants.WEST);
		if ((directions & PositionConstants.NORTH_WEST) == PositionConstants.NORTH_WEST)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.NORTH_WEST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.NORTH_WEST);
		if ((directions & PositionConstants.NORTH) != 0)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.NORTH);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.NORTH);
		if ((directions & PositionConstants.NORTH_EAST) == PositionConstants.NORTH_EAST)
			ResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
					PositionConstants.NORTH_EAST);
		else
			NonResizableHandleKit.addHandle((GraphicalEditPart)getHost(), list, 
						PositionConstants.NORTH_EAST);	
	} else
		ResizableHandleKit.addHandles((GraphicalEditPart)getHost(), list);
	
 	return list;
}

/**
 * Dispatches erase requests to more specific methods.
 * @see org.eclipse.gef.EditPolicy#eraseSourceFeedback(org.eclipse.gef.Request)
 */
public void eraseSourceFeedback(Request request) {
	if (REQ_RESIZE.equals(request.getType()))
		eraseChangeBoundsFeedback((ChangeBoundsRequest) request);
	else
		super.eraseSourceFeedback(request);
}

/**
 * @see org.eclipse.gef.EditPolicy#getCommand(org.eclipse.gef.Request)
 */
public Command getCommand(Request request) {
	if (REQ_RESIZE.equals(request.getType()))
		return getResizeCommand((ChangeBoundsRequest)request);

	return super.getCommand(request);
}

/**
 * Returns the current resize directions integer that depicts which handles
 * can be resized on this object.
 * 
 * @return handle directions that can be resized
 */
public int getResizeDirections() {
	return directions;
}

/**
 * Returns the command contribution for the given resize request. By default, the request
 * is redispatched to the host's parent as a {@link
 * org.eclipse.gef.RequestConstants#REQ_RESIZE_CHILDREN}.  The parent's editpolicies
 * determine how to perform the resize based on the layout manager in use.
 * @param request the resize request
 * @return the command contribution obtained from the parent
 */
protected Command getResizeCommand(ChangeBoundsRequest request) {
	ChangeBoundsRequest req = new ChangeBoundsRequest(REQ_RESIZE_CHILDREN);
	req.setEditParts(getHost());
	
	req.setMoveDelta(request.getMoveDelta());
	req.setSizeDelta(request.getSizeDelta());
	req.setLocation(request.getLocation());
	req.setExtendedData(request.getExtendedData());
	req.setResizeDirection(request.getResizeDirection());
	return getHost().getParent().getCommand(req);
}

/**
 * Sets the directions in which handles should allow resizing. Valid values are bit-wise
 * combinations of:
 * <UL>
 *   <LI>{@link PositionConstants#NORTH}
 *   <LI>{@link PositionConstants#SOUTH}
 *   <LI>{@link PositionConstants#EAST}
 *   <LI>{@link PositionConstants#WEST}
 * </UL>
 * 
 * @param newDirections the direction in which resizing is allowed
 */
public void setResizeDirections(int newDirections) {
	directions = newDirections;
}

/**
 * @see org.eclipse.gef.EditPolicy#showSourceFeedback(org.eclipse.gef.Request)
 */
public void showSourceFeedback(Request request) {
	if (REQ_RESIZE.equals(request.getType()))
		showChangeBoundsFeedback((ChangeBoundsRequest)request);
	else
		super.showSourceFeedback(request);
}

/**
 * @see org.eclipse.gef.EditPolicy#understandsRequest(org.eclipse.gef.Request)
 */
public boolean understandsRequest(Request request) {
	if (REQ_RESIZE.equals(request.getType()))
		return true;
	return super.understandsRequest(request);
}

}