memoryimagesource.java

《移动Agent技术》一书的所有章节源代码。

/*
 * @(#)MemoryImageSource.java	1.18 96/11/23
 * 
 * Copyright (c) 1995, 1996 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 * 
 * 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.
 * 
 * CopyrightVersion 1.1_beta
 * 
 */

package java.awt.image;

import java.awt.image.ImageConsumer;
import java.awt.image.ImageProducer;
import java.awt.image.ColorModel;
import java.util.Hashtable;
import java.util.Vector;
import java.util.Enumeration;

/**
 * This class is an implementation of the ImageProducer interface which
 * uses an array to produce pixel values for an Image.  Here is an example
 * which calculates a 100x100 image representing a fade from black to blue
 * along the X axis and a fade from black to red along the Y axis:
 * <pre>
 * 
 *	int w = 100;
 *	int h = 100;
 *	int pix[] = new int[w * h];
 *	int index = 0;
 *	for (int y = 0; y < h; y++) {
 *	    int red = (y * 255) / (h - 1);
 *	    for (int x = 0; x < w; x++) {
 *		int blue = (x * 255) / (w - 1);
 *		pix[index++] = (255 << 24) | (red << 16) | blue;
 *	    }
 *	}
 *	Image img = createImage(new MemoryImageSource(w, h, pix, 0, w));
 * 
 * </pre>
 * The MemoryImageSource is also capable of managing a memory image which
 * varies over time to allow animation or custom rendering.  Here is an
 * example showing how to set up the animation source and signal changes
 * in the data (adapted from the MemoryAnimationSourceDemo by Garth Dickie):
 * <pre>
 *
 *	int pixels[];
 *	MemoryImageSource source;
 *
 *	public void init() {
 *	    int width = 50;
 *	    int height = 50;
 *	    int size = width * height;
 *	    pixels = new int[size];
 *
 *	    int value = getBackground().getRGB();
 *	    for (int i = 0; i < size; i++) {
 *		pixels[i] = value;
 *	    }
 *
 *	    source = new MemoryImageSource(width, height, pixels, 0, width);
 *	    source.setAnimated(true);
 *	    image = createImage(source);
 *	}
 *
 *	public void run() {
 *	    Thread me = Thread.currentThread( );
 *	    me.setPriority(Thread.MIN_PRIORITY);
 *
 *	    while (true) {
 *		try {
 *		    thread.sleep(10);
 *		} catch( InterruptedException e ) {
 *		    return;
 *		}
 *
 *		// Modify the values in the pixels array at (x, y, w, h)
 *
 *		// Send the new data to the interested ImageConsumers
 *		source.newPixels(x, y, w, h);
 *	    }
 *	}
 *
 * </pre>
 *
 * @see ImageProducer
 *
 * @version	1.18 11/23/96
 * @author 	Jim Graham
 * @author	Animation capabilities inspired by the
 *		MemoryAnimationSource class written by Garth Dickie
 */
public class MemoryImageSource implements ImageProducer {
    int width;
    int height;
    ColorModel model;
    Object pixels;
    int pixeloffset;
    int pixelscan;
    Hashtable properties;
    Vector theConsumers = new Vector();
    boolean animating;
    boolean fullbuffers;

    /**
     * Constructs an ImageProducer object which uses an array of bytes
     * to produce data for an Image object.
     * @see java.awt.Component#createImage
     */
    public MemoryImageSource(int w, int h, ColorModel cm,
			     byte[] pix, int off, int scan) {
	initialize(w, h, cm, (Object) pix, off, scan, null);
    }

    /**
     * Constructs an ImageProducer object which uses an array of bytes
     * to produce data for an Image object.
     * @see java.awt.Component#createImage
     */
    public MemoryImageSource(int w, int h, ColorModel cm,
			     byte[] pix, int off, int scan, Hashtable props) {
	initialize(w, h, cm, (Object) pix, off, scan, props);
    }

    /**
     * Constructs an ImageProducer object which uses an array of integers
     * to produce data for an Image object.
     * @see java.awt.Component#createImage
     */
    public MemoryImageSource(int w, int h, ColorModel cm,
			     int[] pix, int off, int scan) {
	initialize(w, h, cm, (Object) pix, off, scan, null);
    }

    /**
     * Constructs an ImageProducer object which uses an array of integers
     * to produce data for an Image object.
     * @see java.awt.Component#createImage
     */
    public MemoryImageSource(int w, int h, ColorModel cm,
			     int[] pix, int off, int scan, Hashtable props) {
	initialize(w, h, cm, (Object) pix, off, scan, props);
    }

    private void initialize(int w, int h, ColorModel cm,
			    Object pix, int off, int scan, Hashtable props) {
	width = w;
	height = h;
	model = cm;
	pixels = pix;
	pixeloffset = off;
	pixelscan = scan;
	if (props == null) {
	    props = new Hashtable();
	}
	properties = props;
    }

    /**
     * Constructs an ImageProducer object which uses an array of integers
     * in the default RGB ColorModel to produce data for an Image object.
     * @see java.awt.Component#createImage
     * @see ColorModel#getRGBdefault
     */
    public MemoryImageSource(int w, int h, int pix[], int off, int scan) {
	initialize(w, h, ColorModel.getRGBdefault(),
		   (Object) pix, off, scan, null);
    }

    /**
     * Constructs an ImageProducer object which uses an array of integers
     * in the default RGB ColorModel to produce data for an Image object.
     * @see java.awt.Component#createImage
     * @see ColorModel#getRGBdefault
     */
    public MemoryImageSource(int w, int h, int pix[], int off, int scan,
			     Hashtable props) {
	initialize(w, h, ColorModel.getRGBdefault(),
		   (Object) pix, off, scan, props);
    }

    /**
     * Adds an ImageConsumer to the list of consumers interested in
     * data for this image.
     * @see ImageConsumer
     */
    public synchronized void addConsumer(ImageConsumer ic) {
	if (theConsumers.contains(ic)) {
	    return;
	}
	theConsumers.addElement(ic);
	try {
	    initConsumer(ic);
	    sendPixels(ic, 0, 0, width, height);
	    if (isConsumer(ic)) {
		ic.imageComplete(animating
				 ? ImageConsumer.SINGLEFRAMEDONE
				 : ImageConsumer.STATICIMAGEDONE);
		if (!animating && isConsumer(ic)) {
		    ic.imageComplete(ImageConsumer.IMAGEERROR);
		    removeConsumer(ic);
		}
	    }
	} catch (Exception e) {
	    if (isConsumer(ic)) {
		ic.imageComplete(ImageConsumer.IMAGEERROR);
	    }
	}
    }

    /**
     * Determine if an ImageConsumer is on the list of consumers currently
     * interested in data for this image.
     * @return true if the ImageConsumer is on the list; false otherwise
     * @see ImageConsumer
     */
    public synchronized boolean isConsumer(ImageConsumer ic) {
	return theConsumers.contains(ic);
    }

    /**
     * Remove an ImageConsumer from the list of consumers interested in
     * data for this image.
     * @see ImageConsumer
     */
    public synchronized void removeConsumer(ImageConsumer ic) {
	theConsumers.removeElement(ic);
    }

    /**
     * Adds an ImageConsumer to the list of consumers interested in
     * data for this image, and immediately start delivery of the