/*******************************************************************************
* 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.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Path;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
/**
* This tab demonstrates alpha blending. It draws various shapes and images as alpha values change.
*/
public class AlphaTab extends AnimatedGraphicsTab {
/**
* Creates a font using the specified arguments and returns it. This method takes into account the resident
* platform.
*
* @param face
* The name of the font
* @param points
* The size of the font in point
* @param style
* The style to be applied to the font
*/
static Font createFont(Device device, int points, int style) {
if (SWT.getPlatform() == "win32")
return new Font(device, "Verdana", points, style);
else if (SWT.getPlatform() == "motif")
return new Font(device, "Times", points, style);
else if (SWT.getPlatform() == "gtk")
return new Font(device, "Baekmuk Batang", points, style);
else if (SWT.getPlatform() == "carbon")
return new Font(device, "Verdana", points, style);
else
return new Font(device, "Verdana", points, style);
}
Image alphaImg1, alphaImg2;
/**
* Value used in setAlpha API call. Goes from 0 to 255 and then starts over.
*/
int alphaValue;
/**
* Value used in setAlpha API call. Goes from 0 to 255, then from 255 to 0 and then starts over.
*/
int alphaValue2;
int diameter;
/** random numbers used for positioning "SWT" */
int randX, randY;
boolean reachedMax = false;
public AlphaTab(GraphicsExample example) {
super(example);
}
public void dispose() {
if (alphaImg1 != null) {
alphaImg1.dispose();
alphaImg1 = null;
}
if (alphaImg2 != null) {
alphaImg2.dispose();
alphaImg2 = null;
}
}
public String getCategory() {
return GraphicsExample.getResourceString("Alpha"); //$NON-NLS-1$
}
public String getDescription() {
return GraphicsExample.getResourceString("AlphaDescription"); //$NON-NLS-1$
}
public int getInitialAnimationTime() {
return 20;
}
public String getText() {
return GraphicsExample.getResourceString("Alpha"); //$NON-NLS-1$
}
public void next(int width, int height) {
alphaValue = (alphaValue + 5) % 255;
alphaValue2 = reachedMax ? alphaValue2 - 5 : alphaValue2 + 5;
if (alphaValue2 == 255)
reachedMax = true;
else if (alphaValue2 == 0)
reachedMax = false;
diameter = (diameter + 10) % (width > height ? width : height);
}
/**
* Paint the receiver into the specified GC.
*/
public void paint(GC gc, int width, int height) {
if (!example.checkAdvancedGraphics())
return;
Device device = gc.getDevice();
if (alphaImg1 == null) {
alphaImg1 = GraphicsExample.loadImage(device, GraphicsExample.class, "alpha_img1.png");
alphaImg2 = GraphicsExample.loadImage(device, GraphicsExample.class, "alpha_img2.png");
}
Rectangle rect = alphaImg1.getBounds();
gc.setAlpha(alphaValue);
gc.drawImage(alphaImg1, rect.x, rect.y, rect.width, rect.height, width / 2, height / 2, width / 4, height / 4);
gc.drawImage(alphaImg1, rect.x, rect.y, rect.width, rect.height, 0, 0, width / 4, height / 4);
gc.setAlpha(255 - alphaValue);
gc.drawImage(alphaImg2, rect.x, rect.y, rect.width, rect.height, width / 2, 0, width / 4, height / 4);
gc.drawImage(alphaImg2, rect.x, rect.y, rect.width, rect.height, 0, 3 * height / 4, width / 4, height / 4);
// pentagon
gc.setBackground(device.getSystemColor(SWT.COLOR_DARK_MAGENTA));
gc.fillPolygon(new int[] { width / 10, height / 2, 3 * width / 10, height / 2 - width / 6, 5 * width / 10,
height / 2, 4 * width / 10, height / 2 + width / 6, 2 * width / 10, height / 2 + width / 6 });
gc.setBackground(device.getSystemColor(SWT.COLOR_RED));
// square
gc.setAlpha(alphaValue);
gc.fillRectangle(width / 2, height - 75, 75, 75);
// triangle
gc.setAlpha(alphaValue + 15);
gc.fillPolygon(new int[] { width / 2 + 75, height - 2 * 75, width / 2 + 75, height - 75, width / 2 + 2 * 75,
height - 75 });
// triangle
gc.setAlpha(alphaValue + 30);
gc.fillPolygon(new int[] { width / 2 + 80, height - 2 * 75, width / 2 + 2 * 75, height - 2 * 75,
width / 2 + 2 * 75, height - 80 });
// triangle
gc.setAlpha(alphaValue + 45);
gc.fillPolygon(new int[] { width / 2 + 2 * 75, height - 2 * 75, width / 2 + 3 * 75, height - 2 * 75,
width / 2 + 3 * 75, height - 3 * 75 });
// triangle
gc.setAlpha(alphaValue + 60);
gc.fillPolygon(new int[] { width / 2 + 2 * 75, height - (2 * 75 + 5), width / 2 + 2 * 75, height - 3 * 75,
width / 2 + 3 * 75 - 5, height - 3 * 75 });
// square
gc.setAlpha(alphaValue + 75);
gc.fillRectangle(width / 2 + 3 * 75, height - 4 * 75, 75, 75);
gc.setBackground(device.getSystemColor(SWT.COLOR_GREEN));
// circle in top right corner
gc.setAlpha(alphaValue2);
gc.fillOval(width - 100, 0, 100, 100);
// triangle
gc.setAlpha(alphaValue + 90);
gc.fillPolygon(new int[] { width - 300, 10, width - 100, 10, width - 275, 50 });
// triangle
gc.setAlpha(alphaValue + 105);
gc.fillPolygon(new int[] { width - 10, 100, width - 10, 300, width - 50, 275 });
// quadrilateral shape
gc.setAlpha(alphaValue + 120);
gc.fillPolygon(new int[] { width - 100, 100, width - 200, 150, width - 200, 200, width - 150, 200 });
// blue circles
gc.setBackground(device.getSystemColor(SWT.COLOR_BLUE));
int size = 50;
int alpha = 20;
for (int i = 0; i < 10; i++) {
gc.setAlpha(alphaValue + alpha);
if (i % 2 > 0)
gc.fillOval(width - (i + 1) * size, height - size, size, size);
else
gc.fillOval(width - (i + 1) * size, height - 3 * size / 2, size, size);
alpha = alpha + 20;
}
// SWT string appearing randomly
gc.setAlpha(alphaValue2);
String text = GraphicsExample.getResourceString("SWT");
Font font = AlphaTab.createFont(device, 100, SWT.NONE);
gc.setFont(font);
Point textSize = gc.stringExtent(text);
int textWidth = textSize.x;
int textHeight = textSize.y;
if (alphaValue2 == 0) {
randX = (int) (width * Math.random());
randY = (int) (height * Math.random());
randX = randX > textWidth ? randX - textWidth : randX;
randY = randY > textHeight ? randY - textHeight : randY;
}
gc.drawString(text, randX, randY, true);
font.dispose();
// gray donut
gc.setAlpha(100);
Path path = new Path(device);
path.addArc((width - diameter) / 2, (height - diameter) / 2, diameter, diameter, 0, 360);
path.close();
path.addArc((width - diameter + 25) / 2, (height - diameter + 25) / 2, diameter - 25, diameter - 25, 0, 360);
path.close();
gc.setBackground(device.getSystemColor(SWT.COLOR_GRAY));
gc.fillPath(path);
gc.drawPath(path);
path.dispose();
}
}