GraphicAntialiasTab.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.Path;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
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 antialiasing for graphics. Antialiasing is used for smoothing jagged edges in graphics. This
 * tab allows the user to see the effects of different antialiasing values.
 */
public class GraphicAntialiasTab extends GraphicsTab {

	Combo				aliasCombo;
	int[]				aliasValues	= { SWT.OFF, SWT.DEFAULT, SWT.ON };

	Button				colorButton;
	Menu				menu;
	GraphicsBackground	ovalColorGB;

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

	public void createControlPanel(Composite parent) {

		Composite comp;

		// create drop down combo for antialiasing
		comp = new Composite(parent, SWT.NONE);
		comp.setLayout(new GridLayout(2, false));
		new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("Antialiasing")); //$NON-NLS-1$
		aliasCombo = new Combo(comp, SWT.DROP_DOWN);
		aliasCombo.add("OFF");
		aliasCombo.add("DEFAULT");
		aliasCombo.add("ON");
		aliasCombo.select(0);
		aliasCombo.addListener(SWT.Selection, new Listener() {
			public void handleEvent(Event event) {
				example.redraw();
			}
		});

		ColorMenu cm = new ColorMenu();
		cm.setColorItems(true);
		menu = cm.createMenu(parent.getParent(), new ColorListener() {
			public void setColor(GraphicsBackground gb) {
				ovalColorGB = gb;
				colorButton.setImage(gb.getThumbNail());
				example.redraw();
			}
		});

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

		// initialize the background to the 5th item in the menu (blue)
		ovalColorGB = (GraphicsBackground) menu.getItem(4).getData();

		// color button
		colorButton = new Button(comp, SWT.PUSH);
		colorButton.setText(GraphicsExample.getResourceString("Color")); //$NON-NLS-1$
		colorButton.setImage(ovalColorGB.getThumbNail());
		colorButton.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));
				menu.setLocation(point.x, point.y + bounds.height);
				menu.setVisible(true);
			}
		});
	}

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

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

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

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

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.examples.graphics.GraphicsTab#paint(org.eclipse.swt.graphics.GC, int, int)
	 */
	public void paint(GC gc, int width, int height) {
		if (!example.checkAdvancedGraphics())
			return;
		Device device = gc.getDevice();

		if (ovalColorGB != null && ovalColorGB.getBgColor1() != null)
			gc.setBackground(ovalColorGB.getBgColor1());

		gc.setAntialias(aliasValues[aliasCombo.getSelectionIndex()]);

		Path path = new Path(device);
		float offsetX = 2 * width / 3f, offsetY = height / 3f;
		for (int i = 0; i < 25; i++)
			path.addArc(offsetX - 50 * i, offsetY - 25 * i, 50 + 100 * i, 25 + 50 * i, 0, 360);
		gc.fillPath(path);
		path.dispose();
	}
}