linecaptab.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 caps applicable to a line.
 */
public class LineCapTab extends GraphicsTab {

	Button colorButton;
	GraphicsBackground foreground;
	Menu menu;

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

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

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

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

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

public void createControlPanel(Composite parent) {
	
	Composite comp;
		
	// create color button
	comp = new Composite(parent, SWT.NONE);
	comp.setLayout(new GridLayout());
	
	ColorMenu cm = new ColorMenu();
	cm.setPatternItems(example.checkAdvancedGraphics());
	menu = cm.createMenu(parent.getParent(), new ColorListener() {
		public void setColor(GraphicsBackground gb) {
			foreground = gb;		
			colorButton.setImage(gb.getThumbNail());
			example.redraw();
		}
	});

	// initialize the foreground to the 3rd item in the menu (red)
	foreground = (GraphicsBackground)menu.getItem(2).getData();
	
	// color button
	colorButton = new Button(comp, SWT.PUSH);
	colorButton.setText(GraphicsExample
			.getResourceString("Color")); //$NON-NLS-1$
	colorButton.setImage(foreground.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) {
	Device device = gc.getDevice();
	
	// draw side lines
	gc.setLineWidth(1);
	gc.setLineStyle(SWT.LINE_DOT);
	gc.setForeground(device.getSystemColor(SWT.COLOR_BLACK));
	gc.drawLine(3*width/16, height/6, 3*width/16, 5*height/6);
	gc.drawLine(13*width/16, height/6, 13*width/16, 5*height/6);
	gc.setLineStyle(SWT.LINE_SOLID);
	
	// draw labels
	Font font = new Font(device, getPlatformFont(), 20, SWT.NORMAL);
	gc.setFont(font);

	String text = GraphicsExample.getResourceString("Flat"); //$NON-NLS-1$
	Point size = gc.stringExtent(text);
	gc.drawString(text, (width-size.x)/2, 3*height/12, true);
	text = GraphicsExample.getResourceString("Square"); //$NON-NLS-1$
	size = gc.stringExtent(text);	
	gc.drawString(text, (width-size.x)/2, 5*height/12, true);
	text = GraphicsExample.getResourceString("Round"); //$NON-NLS-1$
	size = gc.stringExtent(text);
	gc.drawString(text, (width-size.x)/2, 7*height/12, true);
	font.dispose();

	Pattern pattern = null;
	if (foreground.getBgColor1() != null) {
		gc.setForeground(foreground.getBgColor1());
	} else if (foreground.getBgImage() != null) {
		pattern = new Pattern(device, foreground.getBgImage());
		gc.setForegroundPattern(pattern);
	}
	
	// draw lines with caps
	gc.setLineWidth(20);
	gc.setLineCap(SWT.CAP_FLAT);
	gc.drawLine(3*width/16, 2*height/6, 13*width/16, 2*height/6);
	gc.setLineCap(SWT.CAP_SQUARE);
	gc.drawLine(3*width/16, 3*height/6, 13*width/16, 3*height/6);
	gc.setLineCap(SWT.CAP_ROUND);
	gc.drawLine(3*width/16, 4*height/6, 13*width/16, 4*height/6);
	
	if (pattern != null) pattern.dispose();	
}

/**
 * Returns the name of a valid font for the resident platform.
 */
static String getPlatformFont() {
	if(SWT.getPlatform() == "win32") {
		return "Arial";	
	} else if (SWT.getPlatform() == "motif") {
		return "Helvetica";		
	} else if (SWT.getPlatform() == "gtk") {
		return "Baekmuk Batang";		
	} else if (SWT.getPlatform() == "carbon") {
		return "Arial";
	} else { // photon, etc ...
		return "Verdana";
	}
}
}