Java tutorial
/* From http://java.sun.com/docs/books/tutorial/index.html */ /* * @(#)Animator.java 1.5 95/11/29 Herb Jellinek * * Copyright (c) 1994-1995 Sun Microsystems, Inc. All Rights Reserved. * * Permission to use, copy, modify, and distribute this software * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and * without fee is hereby granted. * Please refer to the file http://java.sun.com/copy_trademarks.html * for further important copyright and trademark information and to * http://java.sun.com/licensing.html for further important licensing * information for the Java (tm) Technology. * * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. * * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES"). SUN * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR * HIGH RISK ACTIVITIES. */ import java.applet.Applet; import java.applet.AudioClip; import java.awt.Color; import java.awt.Dimension; import java.awt.Event; import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.Point; import java.awt.image.ImageProducer; import java.net.MalformedURLException; import java.net.URL; import java.util.Enumeration; import java.util.Hashtable; import java.util.Vector; /** * An applet that plays a sequence of images, as a loop or a one-shot. Can have * a soundtrack and/or sound effects tied to individual frames. * * @author Herb Jellinek * @version 1.5, 29 Nov 1995 */ public class Animator extends Applet implements Runnable { /** * The images, in display order (Images). */ Vector images = null; /** * Duration of each image (Integers, in milliseconds). */ Hashtable durations = null; /** * Sound effects for each image (AudioClips). */ Hashtable sounds = null; /** * Position of each image (Points). */ Hashtable positions = null; /** * MediaTracker 'class' ID numbers. */ static final int STARTUP_ID = 0; static final int BACKGROUND_ID = 1; static final int ANIMATION_ID = 2; /** * Start-up image URL, if any. */ URL startUpImageURL = null; /** * Start-up image, if any. */ Image startUpImage = null; /** * Background image URL, if any. */ URL backgroundImageURL = null; /** * Background image, if any. */ Image backgroundImage = null; /** * The soundtrack's URL. */ URL soundtrackURL = null; /** * The soundtrack. */ AudioClip soundtrack; /** * Largest width. */ int maxWidth = 0; /** * Largest height. */ int maxHeight = 0; /** * Was there a problem loading the current image? */ boolean imageLoadError = false; /** * The directory or URL from which the images are loaded */ URL imageSource = null; /** * The directory or URL from which the sounds are loaded */ URL soundSource = null; /** * The thread animating the images. */ Thread engine = null; /** * The current loop slot - index into 'images.' */ int frameNum; /** * frameNum as an Object - suitable for use as a Hashtable key. */ Integer frameNumKey; /** * The current X position (for painting). */ int xPos = 0; /** * The current Y position (for painting). */ int yPos = 0; /** * The default number of milliseconds to wait between frames. */ public static final int defaultPause = 3900; /** * The global delay between images, which can be overridden by the PAUSE * parameter. */ int globalPause = defaultPause; /** * Whether or not the thread has been paused by the user. */ boolean userPause = false; /** * Repeat the animation? If false, just play it once. */ boolean repeat; /** * The offscreen image, used in double buffering */ Image offScrImage; /** * The offscreen graphics context, used in double buffering */ Graphics offScrGC; /** * The MediaTracker we use to load our images. */ MediaTracker tracker; /** * Can we paint yet? */ boolean loaded = false; /** * Was there an initialization error? */ boolean error = false; /** * What we call an image file in messages. */ final static String imageLabel = "image"; /** * What we call a sound file in messages. */ final static String soundLabel = "sound"; /** * Print silly debugging info? */ final boolean debug = false; /** * Applet info. */ public String getAppletInfo() { return "Animator v1.5, by Herb Jellinek"; } /** * Parameter info. */ public String[][] getParameterInfo() { String[][] info = { { "imagesource", "URL", "a directory" }, { "startup", "URL", "displayed at startup" }, { "background", "URL", "displayed as background" }, { "startimage", "int", "start index" }, { "endimage", "int", "end index" }, { "namepattern", "URL", "used to generate indexed names" }, { "pause", "int", "milliseconds" }, { "pauses", "ints", "milliseconds" }, { "repeat", "boolean", "repeat or not" }, { "positions", "coordinates", "path" }, { "soundsource", "URL", "audio directory" }, { "soundtrack", "URL", "background music" }, { "sounds", "URLs", "audio samples" }, }; return info; } /** * Print silly debugging info. */ void dbg(String s) { if (debug) { System.out.println("> " + s); } } /** * Local version of getParameter for debugging purposes. */ public String getParameter(String key) { String result = super.getParameter(key); dbg("getParameter(" + key + ") = " + result); return result; } final int setFrameNum(int newFrameNum) { frameNumKey = new Integer(frameNum = newFrameNum); return frameNum; } void updateMaxDims(Dimension dim) { maxWidth = Math.max(dim.width, maxWidth); maxHeight = Math.max(dim.height, maxHeight); dbg("New width = " + maxWidth + ", height = " + maxHeight); } /** * Parse the IMAGES parameter. It looks like 1|2|3|4|5, etc., where each * number (item) names a source image. * * @return a Vector of (URL) image file names. */ Vector parseImages(String attr) throws MalformedURLException { Vector result = new Vector(10); for (int i = 0; i < attr.length();) { int next = attr.indexOf('|', i); if (next == -1) next = attr.length(); String file = attr.substring(i, next); result.addElement(new URL(imageSource, "T" + file + ".gif")); i = next + 1; } return result; } /** * Fetch the images named in the argument, updating maxWidth and maxHeight * as we go. Is restartable. * * @param images * a Vector of URLs * @return true if all went well, false otherwise. */ boolean fetchImages(Vector images) { int i; int size = images.size(); for (i = 0; i < size; i++) { Object o = images.elementAt(i); if (o instanceof URL) { URL url = (URL) o; tellLoadingMsg(url, imageLabel); Image im = getImage(url); tracker.addImage(im, ANIMATION_ID); images.setElementAt(im, i); } } try { tracker.waitForID(ANIMATION_ID); } catch (InterruptedException e) { } if (tracker.isErrorID(ANIMATION_ID)) { return false; } for (i = 0; i < size; i++) { updateMaxDims(getImageDimensions((Image) images.elementAt(i))); } return true; } /** * Parse the SOUNDS parameter. It looks like train.au||hello.au||stop.au, * etc., where each item refers to a source image. Empty items mean that the * corresponding image has no associated sound. * * @return a Hashtable of SoundClips keyed to Integer frame numbers. */ Hashtable parseSounds(String attr, Vector images) throws MalformedURLException { Hashtable result = new Hashtable(); int imageNum = 0; int numImages = images.size(); for (int i = 0; i < attr.length();) { if (imageNum >= numImages) break; int next = attr.indexOf('|', i); if (next == -1) next = attr.length(); String sound = attr.substring(i, next); if (sound.length() != 0) { result.put(new Integer(imageNum), new URL(soundSource, sound)); } i = next + 1; imageNum++; } return result; } /** * Fetch the sounds named in the argument. Is restartable. * * @return URL of the first bogus file we hit, null if OK. */ URL fetchSounds(Hashtable sounds) { for (Enumeration e = sounds.keys(); e.hasMoreElements();) { Integer num = (Integer) e.nextElement(); Object o = sounds.get(num); if (o instanceof URL) { URL file = (URL) o; tellLoadingMsg(file, soundLabel); try { sounds.put(num, getAudioClip(file)); } catch (Exception ex) { return file; } } } return null; } /** * Parse the PAUSES parameter. It looks like 1000|500|||750, etc., where * each item corresponds to a source image. Empty items mean that the * corresponding image has no special duration, and should use the global * one. * * @return a Hashtable of Integer pauses keyed to Integer frame numbers. */ Hashtable parseDurations(String attr, Vector images) { Hashtable result = new Hashtable(); int imageNum = 0; int numImages = images.size(); for (int i = 0; i < attr.length();) { if (imageNum >= numImages) break; int next = attr.indexOf('|', i); if (next == -1) next = attr.length(); if (i != next - 1) { int duration = Integer.parseInt(attr.substring(i, next)); result.put(new Integer(imageNum), new Integer(duration)); } else { result.put(new Integer(imageNum), new Integer(globalPause)); } i = next + 1; imageNum++; } return result; } /** * Parse a String of form xxx@yyy and return a Point. */ Point parsePoint(String s) throws ParseException { int atPos = s.indexOf('@'); if (atPos == -1) throw new ParseException("Illegal position: " + s); return new Point(Integer.parseInt(s.substring(0, atPos)), Integer.parseInt(s.substring(atPos + 1))); } /** * Parse the POSITIONS parameter. It looks like 10@30|11@31|||12@20, etc., * where each item is an X@Y coordinate corresponding to a source image. * Empty items mean that the corresponding image has the same position as * the preceding one. * * @return a Hashtable of Points keyed to Integer frame numbers. */ Hashtable parsePositions(String param, Vector images) throws ParseException { Hashtable result = new Hashtable(); int imageNum = 0; int numImages = images.size(); for (int i = 0; i < param.length();) { if (imageNum >= numImages) break; int next = param.indexOf('|', i); if (next == -1) next = param.length(); if (i != next) { result.put(new Integer(imageNum), parsePoint(param.substring(i, next))); } i = next + 1; imageNum++; } return result; } /** * Get the dimensions of an image. * * @return the image's dimensions. */ Dimension getImageDimensions(Image im) { return new Dimension(im.getWidth(null), im.getHeight(null)); } /** * Substitute an integer some number of times in a string, subject to * parameter strings embedded in the string. Parameter strings: %N - * substitute the integer as is, with no padding. % <digit>, for example %5 - * substitute the integer left-padded with zeros to <digits>digits wide. %% - * substitute a '%' here. * * @param inStr * the String to substitute within * @param theInt * the int to substitute. */ String doSubst(String inStr, int theInt) { String padStr = "0000000000"; int length = inStr.length(); StringBuffer result = new StringBuffer(length); for (int i = 0; i < length;) { char ch = inStr.charAt(i); if (ch == '%') { i++; if (i == length) { result.append(ch); } else { ch = inStr.charAt(i); if (ch == 'N') { // just stick in the number, unmolested result.append(theInt + ""); i++; } else { int pad; if ((pad = Character.digit(ch, 10)) != -1) { // we've got a width value String numStr = theInt + ""; String scr = padStr + numStr; result.append(scr.substring(scr.length() - pad)); i++; } else { result.append(ch); i++; } } } } else { result.append(ch); i++; } } return result.toString(); } /** * Stuff a range of image names into a Vector. * * @return a Vector of image URLs. */ Vector prepareImageRange(int startImage, int endImage, String pattern) throws MalformedURLException { Vector result = new Vector(Math.abs(endImage - startImage) + 1); if (pattern == null) { pattern = "T%N.gif"; } if (startImage > endImage) { for (int i = startImage; i >= endImage; i--) { result.addElement(new URL(imageSource, doSubst(pattern, i))); } } else { for (int i = startImage; i <= endImage; i++) { result.addElement(new URL(imageSource, doSubst(pattern, i))); } } return result; } /** * Initialize the applet. Get parameters. */ public void init() { tracker = new MediaTracker(this); try { String param = getParameter("IMAGESOURCE"); imageSource = (param == null) ? getDocumentBase() : new URL(getDocumentBase(), param + "/"); param = getParameter("PAUSE"); globalPause = (param != null) ? Integer.parseInt(param) : defaultPause; param = getParameter("REPEAT"); repeat = (param == null) ? true : (param.equalsIgnoreCase("yes") || param.equalsIgnoreCase("true")); int startImage = 1; int endImage = 1; param = getParameter("ENDIMAGE"); if (param != null) { endImage = Integer.parseInt(param); param = getParameter("STARTIMAGE"); if (param != null) { startImage = Integer.parseInt(param); } param = getParameter("NAMEPATTERN"); images = prepareImageRange(startImage, endImage, param); } else { param = getParameter("STARTIMAGE"); if (param != null) { startImage = Integer.parseInt(param); param = getParameter("NAMEPATTERN"); images = prepareImageRange(startImage, endImage, param); } else { param = getParameter("IMAGES"); if (param == null) { showStatus("No legal IMAGES, STARTIMAGE, or ENDIMAGE " + "specified."); return; } else { images = parseImages(param); } } } param = getParameter("BACKGROUND"); if (param != null) { backgroundImageURL = new URL(imageSource, param); } param = getParameter("STARTUP"); if (param != null) { startUpImageURL = new URL(imageSource, param); } param = getParameter("SOUNDSOURCE"); soundSource = (param == null) ? imageSource : new URL(getDocumentBase(), param + "/"); param = getParameter("SOUNDS"); if (param != null) { sounds = parseSounds(param, images); } param = getParameter("PAUSES"); if (param != null) { durations = parseDurations(param, images); } param = getParameter("POSITIONS"); if (param != null) { positions = parsePositions(param, images); } param = getParameter("SOUNDTRACK"); if (param != null) { soundtrackURL = new URL(soundSource, param); } } catch (MalformedURLException e) { showParseError(e); } catch (ParseException e) { showParseError(e); } setFrameNum(0); } void tellLoadingMsg(String file, String fileType) { showStatus("Animator: loading " + fileType + " " + file); } void tellLoadingMsg(URL url, String fileType) { tellLoadingMsg(url.toExternalForm(), fileType); } void clearLoadingMessage() { showStatus(""); } void loadError(String fileName, String fileType) { String errorMsg = "Animator: Couldn't load " + fileType + " " + fileName; showStatus(errorMsg); System.err.println(errorMsg); error = true; repaint(); } void loadError(URL badURL, String fileType) { loadError(badURL.toExternalForm(), fileType); } void showParseError(Exception e) { String errorMsg = "Animator: Parse error: " + e; showStatus(errorMsg); System.err.println(errorMsg); error = true; repaint(); } void startPlaying() { if (soundtrack != null) { soundtrack.loop(); } } void stopPlaying() { if (soundtrack != null) { soundtrack.stop(); } } /** * Run the animation. This method is called by class Thread. * * @see java.lang.Thread */ public void run() { Thread me = Thread.currentThread(); URL badURL; me.setPriority(Thread.MIN_PRIORITY); if (!loaded) { try { // ... to do a bunch of loading. if (startUpImageURL != null) { tellLoadingMsg(startUpImageURL, imageLabel); startUpImage = getImage(startUpImageURL); tracker.addImage(startUpImage, STARTUP_ID); tracker.waitForID(STARTUP_ID); if (tracker.isErrorID(STARTUP_ID)) { loadError(startUpImageURL, "start-up image"); } Dimension size = getImageDimensions(startUpImage); resize(size.width, size.height); repaint(); } if (backgroundImageURL != null) { tellLoadingMsg(backgroundImageURL, imageLabel); backgroundImage = getImage(backgroundImageURL); tracker.addImage(backgroundImage, BACKGROUND_ID); tracker.waitForID(BACKGROUND_ID); if (tracker.isErrorID(BACKGROUND_ID)) { loadError(backgroundImageURL, "background image"); } updateMaxDims(getImageDimensions(backgroundImage)); repaint(); } // Fetch the animation frames if (!fetchImages(images)) { // Need to add method to MediaTracker to return // files that caused errors during loading. loadError("an image", imageLabel); return; } if (soundtrackURL != null && soundtrack == null) { tellLoadingMsg(soundtrackURL, imageLabel); soundtrack = getAudioClip(soundtrackURL); if (soundtrack == null) { loadError(soundtrackURL, "soundtrack"); return; } } if (sounds != null) { badURL = fetchSounds(sounds); if (badURL != null) { loadError(badURL, soundLabel); return; } } clearLoadingMessage(); offScrImage = createImage(maxWidth, maxHeight); offScrGC = offScrImage.getGraphics(); offScrGC.setColor(Color.white); resize(maxWidth, maxHeight); loaded = true; error = false; } catch (Exception e) { error = true; e.printStackTrace(); } } if (userPause) { return; } if (repeat || frameNum < images.size()) { startPlaying(); } try { if (images.size() > 1) { while (maxWidth > 0 && maxHeight > 0 && engine == me) { if (frameNum >= images.size()) { if (!repeat) { return; } setFrameNum(0); } repaint(); if (sounds != null) { AudioClip clip = (AudioClip) sounds.get(frameNumKey); if (clip != null) { clip.play(); } } try { Integer pause = null; if (durations != null) { pause = (Integer) durations.get(frameNumKey); } if (pause == null) { Thread.sleep(globalPause); } else { Thread.sleep(pause.intValue()); } } catch (InterruptedException e) { // Should we do anything? } setFrameNum(frameNum + 1); } } } finally { stopPlaying(); } } /** * No need to clear anything; just paint. */ public void update(Graphics g) { paint(g); } /** * Paint the current frame. */ public void paint(Graphics g) { if (error || !loaded) { if (startUpImage != null) { if (tracker.checkID(STARTUP_ID)) { g.drawImage(startUpImage, 0, 0, this); } } else { if (backgroundImage != null) { if (tracker.checkID(BACKGROUND_ID)) { g.drawImage(backgroundImage, 0, 0, this); } } else { g.clearRect(0, 0, maxWidth, maxHeight); } } } else { if ((images != null) && (images.size() > 0)) { if (frameNum < images.size()) { if (backgroundImage == null) { offScrGC.fillRect(0, 0, maxWidth, maxHeight); } else { offScrGC.drawImage(backgroundImage, 0, 0, this); } Image image = (Image) images.elementAt(frameNum); Point pos = null; if (positions != null) { pos = (Point) positions.get(frameNumKey); } if (pos != null) { xPos = pos.x; yPos = pos.y; } offScrGC.drawImage(image, xPos, yPos, this); g.drawImage(offScrImage, 0, 0, this); } else { // no more animation, but need to draw something dbg("No more animation; drawing last image."); if (backgroundImage == null) { g.fillRect(0, 0, maxWidth, maxHeight); } else { g.drawImage(backgroundImage, 0, 0, this); } g.drawImage((Image) images.lastElement(), 0, 0, this); } } } } /** * Start the applet by forking an animation thread. */ public void start() { if (engine == null) { engine = new Thread(this); engine.start(); } } /** * Stop the insanity, um, applet. */ public void stop() { if (engine != null && engine.isAlive()) { engine.stop(); } engine = null; } /** * Pause the thread when the user clicks the mouse in the applet. If the * thread has stopped (as in a non-repeat performance), restart it. */ public boolean handleEvent(Event evt) { if (evt.id == Event.MOUSE_DOWN) { if (loaded) { if (engine != null && engine.isAlive()) { if (userPause) { engine.resume(); startPlaying(); } else { engine.suspend(); stopPlaying(); } userPause = !userPause; } else { userPause = false; setFrameNum(0); engine = new Thread(this); engine.start(); } } return true; } else { return super.handleEvent(evt); } } } class ParseException extends Exception { ParseException(String s) { super(s); } } class ImageNotFoundException extends Exception { ImageNotFoundException(ImageProducer source) { super(source + ""); } }