introtab.java

SUN公司eclipse3.2.2经典例子

/*******************************************************************************
 * Copyright (c) 2000, 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 java.util.*;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;

public class IntroTab extends AnimatedGraphicsTab {
	
	Font font;
	Image image;
	Random random = new Random();
	float x, y;
    float incX = 10.0f;
	float incY = 5.0f;
	int textWidth, textHeight;
	String text = GraphicsExample.getResourceString("SWT");
	
public IntroTab(GraphicsExample example) {
	super(example);
}

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

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

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

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

public void next(int width, int height) {
    x += incX;
    y += incY;
	float random = (float)Math.random(); 
    if (x + textWidth > width) {
        x = width - textWidth;
        incX = random * -width / 16 - 1;
    }
    if (x < 0) {
        x = 0;
        incX = random * width / 16 + 1;
    }
    if (y + textHeight > height) {
        y = (height - textHeight)- 2;
        incY = random * -height / 16 - 1;
    }
    if (y < 0) {
        y = 0;
        incY = random * height / 16 + 1;
    }
}

public void paint(GC gc, int width, int height) {
	if (!example.checkAdvancedGraphics()) return;
	Device device = gc.getDevice();
	if (image == null) {
		image = example.loadImage(device, "irmaos.jpg");
		Rectangle rect = image.getBounds();
		FontData fd = device.getSystemFont().getFontData()[0];
		font = new Font(device, fd.getName(), rect.height / 4, SWT.BOLD);
		gc.setFont(font);
		Point size = gc.stringExtent(text);
		textWidth = size.x;
		textHeight = size.y;
	}
	Path path = new Path(device);
	path.addString(text, x, y, font);
	gc.setClipping(path);
	Rectangle rect = image.getBounds();
	gc.drawImage(image, 0, 0, rect.width, rect.height, 0, 0, width, height);
	gc.setClipping((Rectangle)null);
	gc.setForeground(device.getSystemColor(SWT.COLOR_BLUE));
	gc.drawPath(path);
	path.dispose();
}
}