/******************************************************************************* * 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 Common Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/cpl-v10.html *  * Contributors: *     IBM Corporation - initial API and implementation *******************************************************************************/package org.eclipse.swt.graphics;import java.io.*;import java.util.Vector;import org.eclipse.swt.*;import org.eclipse.swt.internal.Compatibility;import org.eclipse.swt.internal.image.*;/** * Instances of this class are used to load images from, * and save images to, a file or stream. * <p> * Currently supported image formats are: * </p><ul> * <li>BMP (Windows Bitmap)</li> * <li>ICO (Windows Icon)</li> * <li>JPEG</li> * <li>GIF</li> * <li>PNG</li> * </ul> * <code>ImageLoaders</code> can be used to: * <ul> * <li>load/save single images in all formats</li> * <li>load/save multiple images (GIF/ICO)</li> * <li>load/save animated GIF images</li> * <li>load interlaced GIF/PNG images</li> * <li>load progressive JPEG images</li> * </ul> */ public class ImageLoader {		/**	 * the array of ImageData objects in this ImageLoader.	 * This array is read in when the load method is called,	 * and it is written out when the save method is called	 */	public ImageData[] data;		/**	 * the width of the logical screen on which the images	 * reside, in pixels (this corresponds to the GIF89a	 * Logical Screen Width value)	 */	public int logicalScreenWidth;	/**	 * the height of the logical screen on which the images	 * reside, in pixels (this corresponds to the GIF89a	 * Logical Screen Height value)	 */	public int logicalScreenHeight;	/**	 * the background pixel for the logical screen (this 	 * corresponds to the GIF89a Background Color Index value).	 * The default is -1 which means 'unspecified background'	 * 	 */	public int backgroundPixel;	/**	 * the number of times to repeat the display of a sequence	 * of animated images (this corresponds to the commonly-used	 * GIF application extension for "NETSCAPE 2.0 01")	 */	public int repeatCount;			/*	 * the set of ImageLoader event listeners, created on demand	 */	Vector imageLoaderListeners;/** * Construct a new empty ImageLoader. */public ImageLoader() {	reset();}/** * Resets the fields of the ImageLoader, except for the * <code>imageLoaderListeners</code> field. */void reset() {	data = null;	logicalScreenWidth = 0;	logicalScreenHeight = 0;	backgroundPixel = -1;	repeatCount = 1;}/** * Loads an array of <code>ImageData</code> objects from the * specified input stream. Throws an error if either an error * occurs while loading the images, or if the images are not * of a supported type. Returns the loaded image data array. * * @param stream the input stream to load the images from * @return an array of <code>ImageData</code> objects loaded from the specified input stream * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the stream is null</li> * </ul> * @exception SWTException <ul> *    <li>ERROR_INVALID_IMAGE - if the image file contains invalid data</li> *    <li>ERROR_IO - if an input/output error occurs while reading data</li> * </ul> */public ImageData[] load(InputStream stream) {	if (stream == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	reset();	data = FileFormat.load(stream, this);	return data;}/** * Loads an array of <code>ImageData</code> objects from the * file with the specified name. Throws an error if either * an error occurs while loading the images, or if the images are * not of a supported type. Returns the loaded image data array. * * @param filename the name of the file to load the images from * @return an array of <code>ImageData</code> objects loaded from the specified file * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the file name is null</li> * </ul> * @exception SWTException <ul> *    <li>ERROR_INVALID_IMAGE - if the image file contains invalid data</li> *    <li>ERROR_IO - if an IO error occurs while reading data</li> * </ul> */public ImageData[] load(String filename) {	if (filename == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	InputStream stream = null;	try {		stream = Compatibility.newFileInputStream(filename);		return load(stream);	} catch (IOException e) {		SWT.error(SWT.ERROR_IO, e);	} finally {		try {			if (stream != null) stream.close();		} catch (IOException e) {			// Ignore error		}	}	return null;}/** * Saves the image data in this ImageLoader to the specified stream. * The format parameter can have one of the following values: * <dl> * <dt><code>IMAGE_BMP</code></dt> * <dd>Windows BMP file format, no compression</dd> * <dt><code>IMAGE_BMP_RLE</code></dt> * <dd>Windows BMP file format, RLE compression if appropriate</dd> * <dt><code>IMAGE_GIF</code></dt> * <dd>GIF file format</dd> * <dt><code>IMAGE_ICO</code></dt> * <dd>Windows ICO file format</dd> * <dt><code>IMAGE_JPEG</code></dt> * <dd>JPEG file format</dd> * <dt><code>IMAGE_PNG</code></dt> * <dd>PNG file format</dd> * </dl> * * @param stream the output stream to write the images to * @param format the format to write the images in * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the stream is null</li> * </ul> * @exception SWTException <ul> *    <li>ERROR_INVALID_IMAGE if the image data contains invalid data</li> *    <li>ERROR_IO if an IO error occurs while writing to the stream</li> * </ul> */public void save(OutputStream stream, int format) {	if (stream == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	FileFormat.save(stream, format, this);}/** * Saves the image data in this ImageLoader to a file with the specified name. * The format parameter can have one of the following values: * <dl> * <dt><code>IMAGE_BMP</code></dt> * <dd>Windows BMP file format, no compression</dd> * <dt><code>IMAGE_BMP_RLE</code></dt> * <dd>Windows BMP file format, RLE compression if appropriate</dd> * <dt><code>IMAGE_GIF</code></dt> * <dd>GIF file format</dd> * <dt><code>IMAGE_ICO</code></dt> * <dd>Windows ICO file format</dd> * <dt><code>IMAGE_JPEG</code></dt> * <dd>JPEG file format</dd> * <dt><code>IMAGE_PNG</code></dt> * <dd>PNG file format</dd> * </dl> * * @param filename the name of the file to write the images to * @param format the format to write the images in * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the file name is null</li> * </ul> * @exception SWTException <ul> *    <li>ERROR_INVALID_IMAGE if the image data contains invalid data</li> *    <li>ERROR_IO if an IO error occurs while writing to the file</li> * </ul> */public void save(String filename, int format) {	if (filename == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);	OutputStream stream = null;	try {		stream = Compatibility.newFileOutputStream(filename);	} catch (IOException e) {		SWT.error(SWT.ERROR_IO, e);	}	save(stream, format);}/**	  * Adds a listener to receive image loader events. * <p> * An ImageLoaderListener should be added before invoking * one of the receiver's load methods. The listener's  * <code>imageDataLoaded</code> method is called when image * data has been partially loaded, as is supported by interlaced * GIF/PNG or progressive JPEG images. * * @param listener the ImageLoaderListener to add * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li> * </ul> *  * @see ImageLoaderListener * @see ImageLoaderEvent */public void addImageLoaderListener(ImageLoaderListener listener) {	if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);	if (imageLoaderListeners == null) {		imageLoaderListeners = new Vector();	}	imageLoaderListeners.addElement(listener);}/**	  * Removes a listener that was receiving image loader events. * * @param listener the ImageLoaderListener to remove * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li> * </ul> *  * @see #addImageLoaderListener(ImageLoaderListener) */public void removeImageLoaderListener(ImageLoaderListener listener) {	if (listener == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);	if (imageLoaderListeners == null) return;	imageLoaderListeners.removeElement(listener);}/**	  * Returns <code>true</code> if the receiver has image loader * listeners, and <code>false</code> otherwise. * * @return <code>true</code> if there are <code>ImageLoaderListener</code>s, and <code>false</code> otherwise * * @see #addImageLoaderListener(ImageLoaderListener) * @see #removeImageLoaderListener(ImageLoaderListener) */public boolean hasListeners() {	return imageLoaderListeners != null && imageLoaderListeners.size() > 0;}/**	  * Notifies all image loader listeners that an image loader event * has occurred. Pass the specified event object to each listener. * * @param event the <code>ImageLoaderEvent</code> to send to each <code>ImageLoaderListener</code> */public void notifyListeners(ImageLoaderEvent event) {	if (!hasListeners()) return;	int size = imageLoaderListeners.size();	for (int i = 0; i < size; i++) {		ImageLoaderListener listener = (ImageLoaderListener) imageLoaderListeners.elementAt(i);		listener.imageDataLoaded(event);	}}}