Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2004 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.snippets; /* * Image example snippet: display an animated GIF * * For a list of all SWT example snippets see * http://www.eclipse.org/swt/snippets/ */ import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.graphics.Color; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.ImageData; import org.eclipse.swt.graphics.ImageLoader; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.FileDialog; import org.eclipse.swt.widgets.Shell; public class AnimatedGIFDisplay { static Display display; static Shell shell; static GC shellGC; static Color shellBackground; static ImageLoader loader; static ImageData[] imageDataArray; static Thread animateThread; static Image image; static final boolean useGIFBackground = false; public static void main(String[] args) { display = new Display(); shell = new Shell(display); shell.setSize(300, 300); shell.open(); shellGC = new GC(shell); shellBackground = shell.getBackground(); FileDialog dialog = new FileDialog(shell); dialog.setFilterExtensions(new String[] { "*.gif" }); String fileName = dialog.open(); if (fileName != null) { loader = new ImageLoader(); try { imageDataArray = loader.load(fileName); if (imageDataArray.length > 1) { animateThread = new Thread("Animation") { public void run() { /* * Create an off-screen image to draw on, and fill it with the * shell background. */ Image offScreenImage = new Image(display, loader.logicalScreenWidth, loader.logicalScreenHeight); GC offScreenImageGC = new GC(offScreenImage); offScreenImageGC.setBackground(shellBackground); offScreenImageGC.fillRectangle(0, 0, loader.logicalScreenWidth, loader.logicalScreenHeight); try { /* Create the first image and draw it on the off-screen image. */ int imageDataIndex = 0; ImageData imageData = imageDataArray[imageDataIndex]; if (image != null && !image.isDisposed()) image.dispose(); image = new Image(display, imageData); offScreenImageGC.drawImage(image, 0, 0, imageData.width, imageData.height, imageData.x, imageData.y, imageData.width, imageData.height); /* * Now loop through the images, creating and drawing each one on * the off-screen image before drawing it on the shell. */ int repeatCount = loader.repeatCount; while (loader.repeatCount == 0 || repeatCount > 0) { switch (imageData.disposalMethod) { case SWT.DM_FILL_BACKGROUND: /* Fill with the background color before drawing. */ Color bgColor = null; if (useGIFBackground && loader.backgroundPixel != -1) { bgColor = new Color(display, imageData.palette.getRGB(loader.backgroundPixel)); } offScreenImageGC.setBackground(bgColor != null ? bgColor : shellBackground); offScreenImageGC.fillRectangle(imageData.x, imageData.y, imageData.width, imageData.height); if (bgColor != null) bgColor.dispose(); break; case SWT.DM_FILL_PREVIOUS: /* Restore the previous image before drawing. */ offScreenImageGC.drawImage(image, 0, 0, imageData.width, imageData.height, imageData.x, imageData.y, imageData.width, imageData.height); break; } imageDataIndex = (imageDataIndex + 1) % imageDataArray.length; imageData = imageDataArray[imageDataIndex]; image.dispose(); image = new Image(display, imageData); offScreenImageGC.drawImage(image, 0, 0, imageData.width, imageData.height, imageData.x, imageData.y, imageData.width, imageData.height); /* Draw the off-screen image to the shell. */ shellGC.drawImage(offScreenImage, 0, 0); /* * Sleep for the specified delay time (adding commonly-used * slow-down fudge factors). */ try { int ms = imageData.delayTime * 10; if (ms < 20) ms += 30; if (ms < 30) ms += 10; Thread.sleep(ms); } catch (InterruptedException e) { } /* * If we have just drawn the last image, decrement the repeat * count and start again. */ if (imageDataIndex == imageDataArray.length - 1) repeatCount--; } } catch (SWTException ex) { System.out.println("There was an error animating the GIF"); } finally { if (offScreenImage != null && !offScreenImage.isDisposed()) offScreenImage.dispose(); if (offScreenImageGC != null && !offScreenImageGC.isDisposed()) offScreenImageGC.dispose(); if (image != null && !image.isDisposed()) image.dispose(); } } }; animateThread.setDaemon(true); animateThread.start(); } } catch (SWTException ex) { System.out.println("There was an error loading the GIF"); } } while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } }