RegionClippingTab.java

/*******************************************************************************
 * Copyright (c) 2006 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.examples.graphics;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Device;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Menu;

/**
 * This tab demonstrates how to apply a region clipping and the effects of applying one.
 */
public class RegionClippingTab extends GraphicsTab {

	private Combo	clippingCb;
	private Button	colorButton1, colorButton2;
	private GraphicsBackground	colorGB1, colorGB2;
	private Menu				menu1, menu2;

	public RegionClippingTab(GraphicsExample example) {
		super(example);
	}

	/**
	 * Creates the widgets used to control the drawing.
	 */
	public void createControlPanel(Composite parent) {
		// create drop down combo for choosing clipping
		Composite comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout(2, false));

		new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("Clipping")); //$NON-NLS-1$
		clippingCb = new Combo(comp, SWT.DROP_DOWN);
		clippingCb.add(GraphicsExample.getResourceString("Region1")); //$NON-NLS-1$
		clippingCb.add(GraphicsExample.getResourceString("Region2")); //$NON-NLS-1$
		clippingCb.add(GraphicsExample.getResourceString("Add")); //$NON-NLS-1$
		clippingCb.add(GraphicsExample.getResourceString("Sub")); //$NON-NLS-1$
		clippingCb.add(GraphicsExample.getResourceString("Inter")); //$NON-NLS-1$
		clippingCb.select(0);
		clippingCb.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				example.redraw();
			}
		});

		// color menu
		ColorMenu cm = new ColorMenu();
		menu1 = cm.createMenu(parent.getParent(), new ColorListener() {
			public void setColor(GraphicsBackground gb) {
				colorGB1 = gb;
				colorButton1.setImage(gb.getThumbNail());
				example.redraw();
			}
		});
		menu2 = cm.createMenu(parent.getParent(), new ColorListener() {
			public void setColor(GraphicsBackground gb) {
				colorGB2 = gb;
				colorButton2.setImage(gb.getThumbNail());
				example.redraw();
			}
		});

		// initialize the color to blue
		colorGB1 = (GraphicsBackground) menu1.getItem(4).getData();
		// initialize the color to red
		colorGB2 = (GraphicsBackground) menu2.getItem(2).getData();

		// color button 1
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout(2, false));

		colorButton1 = new Button(comp, SWT.PUSH);
		colorButton1.setText(GraphicsExample.getResourceString("Color1")); //$NON-NLS-1$
		colorButton1.setImage(colorGB1.getThumbNail());
		colorButton1.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				final Button button = (Button) event.widget;
				final Composite parent = button.getParent();
				Rectangle bounds = button.getBounds();
				Point point = parent.toDisplay(new Point(bounds.x, bounds.y));
				menu1.setLocation(point.x, point.y + bounds.height);
				menu1.setVisible(true);
			}
		});

		// color button 2
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout(2, false));

		colorButton2 = new Button(comp, SWT.PUSH);
		colorButton2.setText(GraphicsExample.getResourceString("Color2")); //$NON-NLS-1$
		colorButton2.setImage(colorGB2.getThumbNail());
		colorButton2.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				final Button button = (Button) event.widget;
				final Composite parent = button.getParent();
				Rectangle bounds = button.getBounds();
				Point point = parent.toDisplay(new Point(bounds.x, bounds.y));
				menu2.setLocation(point.x, point.y + bounds.height);
				menu2.setVisible(true);
			}
		});
	}

	public void dispose() {
		if (menu1 != null) {
			menu1.dispose();
			menu1 = null;
		}
		if (menu2 != null) {
			menu2.dispose();
			menu2 = null;
		}
	}

	public String getCategory() {
		return GraphicsExample.getResourceString("Clipping"); //$NON-NLS-1$
	}

	public String getDescription() {
		return GraphicsExample.getResourceString("RegionClippingDescription"); //$NON-NLS-1$
	}

	public String getText() {
		return GraphicsExample.getResourceString("RegionClipping"); //$NON-NLS-1$
	}

	public void paint(GC gc, int width, int height) {
		if (!example.checkAdvancedGraphics())
			return;
		Device device = gc.getDevice();

		// array of coordinate points of polygon 1 (region 1)
		int[] polygon1 = new int[] { 10, height / 2, 9 * width / 16, 10, 9 * width / 16, height - 10 };
		Region region1 = new Region(device);
		region1.add(polygon1);

		// array of coordinate points of polygon 2 (region 2)
		int[] polygon2 = new int[] { 9 * width / 16, 10, 9 * width / 16, height / 8, 7 * width / 16, 2 * height / 8,
				9 * width / 16, 3 * height / 8, 7 * width / 16, 4 * height / 8, 9 * width / 16, 5 * height / 8,
				7 * width / 16, 6 * height / 8, 9 * width / 16, 7 * height / 8, 9 * width / 16, height - 10,
				width - 10, height / 2 };
		Region region2 = new Region(device);
		region2.add(polygon2);

		gc.setAlpha(127);

		int clippingIndex = clippingCb.getSelectionIndex();

		switch (clippingIndex) {
		case 0:
			// region 1
			gc.setClipping(region1);
			gc.setBackground(colorGB1.getBgColor1());
			gc.fillPolygon(polygon1);
			break;
		case 1:
			// region 2
			gc.setClipping(region2);
			gc.setBackground(colorGB2.getBgColor1());
			gc.fillPolygon(polygon2);
			break;
		case 2:
			// add
			region1.add(region2);
			break;
		case 3:
			// sub
			region1.subtract(region2);
			break;
		case 4:
			// intersect
			region1.intersect(region2);
			break;
		}

		if (clippingIndex > 1) {
			gc.setClipping(region1);

			gc.setBackground(colorGB1.getBgColor1());
			gc.fillPolygon(polygon1);

			gc.setBackground(colorGB2.getBgColor1());
			gc.fillPolygon(polygon2);
		}

		region1.dispose();
		region2.dispose();
	}
}