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/*******************************************************************************
* Copyright (c) 2006, 2014 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.*;
/**
* This tab demonstrates alpha blending. It draws various shapes and images as
* alpha values change.
*/
public class AlphaTab extends AnimatedGraphicsTab {
/**
* 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;
boolean reachedMax = false;
int diameter;
/** random numbers used for positioning "SWT" */
int randX, randY;
Image alphaImg1, alphaImg2;
public AlphaTab(GraphicsExample example) {
super(example);
}
@Override
public String getCategory() {
return GraphicsExample.getResourceString("Alpha"); //$NON-NLS-1$
}
@Override
public String getText() {
return GraphicsExample.getResourceString("Alpha"); //$NON-NLS-1$
}
@Override
public String getDescription() {
return GraphicsExample.getResourceString("AlphaDescription"); //$NON-NLS-1$
}
@Override
public int getInitialAnimationTime() {
return 20;
}
@Override
public void dispose() {
if (alphaImg1 != null) {
alphaImg1.dispose();
alphaImg1 = null;
}
if (alphaImg2 != null) {
alphaImg2.dispose();
alphaImg2 = null;
}
}
@Override
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.
*/
@Override
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 = 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();
}
/**
* 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() == "gtk") {
return new Font(device, "Baekmuk Batang", points, style);
} else {
return new Font(device, "Verdana", points, style);
}
}
}
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