linejointab.java

SUN公司eclipse3.2.2经典例子

/*******************************************************************************
 * 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.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This tab demonstrates various line joins. It allows a user to choose from
 * bevel, miter and round.
 */
public class LineJoinTab extends GraphicsTab {
	
	private Combo joinCb;
	private Button colorButton;
	private GraphicsBackground shapeColor;
	private Menu menu;
	private int [] joinValues = new int [] {SWT.JOIN_BEVEL, SWT.JOIN_MITER, SWT.JOIN_ROUND};

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

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

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

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

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

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("LineJoin")); //$NON-NLS-1$
	joinCb = new Combo(comp, SWT.DROP_DOWN);
	joinCb.add(GraphicsExample
			.getResourceString("bevel")); //$NON-NLS-1$
	joinCb.add(GraphicsExample
			.getResourceString("miter")); //$NON-NLS-1$
	joinCb.add(GraphicsExample
			.getResourceString("round")); //$NON-NLS-1$
	joinCb.select(1);
	joinCb.addListener(SWT.Selection, new Listener() {
		public void handleEvent(Event event) {
				example.redraw();
		}
	});
	
	// color menu
	ColorMenu cm = new ColorMenu();
	cm.setPatternItems(example.checkAdvancedGraphics());
	menu = cm.createMenu(parent.getParent(), new ColorListener() {
		public void setColor(GraphicsBackground gb) {
			shapeColor = gb;		
			colorButton.setImage(gb.getThumbNail());
			example.redraw();
		}
	});

	// initialize the shape color to the 4th item in the menu (green)
	shapeColor =(GraphicsBackground)menu.getItem(3).getData();
	
	// color button
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout(2, false));
	
	colorButton = new Button(comp, SWT.PUSH);
	colorButton.setText(GraphicsExample
			.getResourceString("Color")); //$NON-NLS-1$
	colorButton.setImage(shapeColor.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 paint(GC gc, int width, int height) {
	if (!example.checkAdvancedGraphics()) return;
	Device device = gc.getDevice();

	gc.setLineWidth(20);
	gc.setLineJoin(joinValues[joinCb.getSelectionIndex()]);
	
	// set the foreground color or pattern
	Pattern pattern = null;
	if (shapeColor.getBgColor1() != null) {
		gc.setForeground(shapeColor.getBgColor1());
	} else if (shapeColor.getBgImage() != null) {
		pattern = new Pattern(device, shapeColor.getBgImage());
		gc.setForegroundPattern(pattern);
	}
	
	// draw the shape
	Path path = new Path(device);
	path.moveTo(width/2, 25);
	path.lineTo(2*width/3, height/3);
	path.lineTo(width-25, height/2);
	path.lineTo(2*width/3, 2*height/3);
	path.lineTo(width/2, height-25);
	path.lineTo(width/3, 2*height/3);
	path.lineTo(25, height/2);
	path.lineTo(width/3, height/3);
	path.lineTo(width/2, 25);
	path.close();
	gc.drawPath(path);
	path.dispose();
	
	if (pattern != null) pattern.dispose();
}

}