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/* * Copyright (c) 2004, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package sun.swing; import java.awt.*;import java.awt.image.*;import java.util.*; /** * A base class used for icons or images that are expensive to paint. * A subclass will do the following: * <ol> * <li>Invoke <code>paint</code> when you want to paint the image, *     if you are implementing <code>Icon</code> you'll invoke this from *     <code>paintIcon</code>. *     The args argument is useful when additional state is needed. * <li>Override <code>paintToImage</code> to render the image.  The code that *     lives here is equivalent to what previously would go in *     <code>paintIcon</code>, for an <code>Icon</code>. * </ol> * The two ways to use this class are: * <ol> * <li>Invoke <code>paint</code> to draw the cached reprensentation at *     the specified location. * <li>Invoke <code>getImage</code> to get the cached reprensentation and *     draw the image yourself.  This is primarly useful when you are not *     using <code>VolatileImage</code>. * </ol> * * */public abstract class CachedPainter {    // CacheMap maps from class to ImageCache.    private static final Map<Object,ImageCache> cacheMap =                   new HashMap<Object,ImageCache>();      private static ImageCache getCache(Object key) {        synchronized(CachedPainter.class) {            ImageCache cache = cacheMap.get(key);            if (cache == null) {                cache = new ImageCache(1);                cacheMap.put(key, cache);            }            return cache;        }    }     /**     * Creates an instance of <code>CachedPainter</code> that will cache up     * to <code>cacheCount</code> images of this class.     *     * @param cacheCount Max number of images to cache     */    public CachedPainter(int cacheCount) {        getCache(getClass()).setMaxCount(cacheCount);    }     /**     * Renders the cached image to the the passed in <code>Graphic</code>.     * If there is no cached image <code>paintToImage</code> will be invoked.     * <code>paintImage</code> is invoked to paint the cached image.     *     * @param c Component rendering to, this may be null.     * @param g Graphics to paint to     * @param x X-coordinate to render to     * @param y Y-coordinate to render to     * @param w Width to render in     * @param h Height to render in     * @param arg Variable arguments that will be passed to paintToImage     */    public void paint(Component c, Graphics g, int x,                         int y, int w, int h, Object... args) {        if (w <= 0 || h <= 0) {            return;        }        if (c != null) {            synchronized(c.getTreeLock()) {                synchronized(CachedPainter.class) {                    // If c is non-null, synchronize on the tree lock.                    // This is necessary because asking for the                    // GraphicsConfiguration will grab a tree lock.                    paint0(c, g, x, y, w, h, args);                }            }        }        else {            synchronized(CachedPainter.class) {                paint0(c, g, x, y, w, h, args);            }        }    }     private void paint0(Component c, Graphics g, int x,                         int y, int w, int h, Object... args) {        Object key = getClass();        GraphicsConfiguration config = getGraphicsConfiguration(c);        ImageCache cache = getCache(key);        Image image = cache.getImage(key, config, w, h, args);        int attempts = 0;        do {            boolean draw = false;            if (image instanceof VolatileImage) {                // See if we need to recreate the image                switch (((VolatileImage)image).validate(config)) {                case VolatileImage.IMAGE_INCOMPATIBLE:                    ((VolatileImage)image).flush();                    image = null;                    break;                case VolatileImage.IMAGE_RESTORED:                    draw = true;                    break;                }            }            if (image == null) {                // Recreate the image                image = createImage(c, w, h, config, args);                cache.setImage(key, config, w, h, args, image);                draw = true;            }            if (draw) {                // Render to the Image                Graphics g2 = image.getGraphics();                paintToImage(c, image, g2, w, h, args);                g2.dispose();            }             // Render to the passed in Graphics            paintImage(c, g, x, y, w, h, image, args);             // If we did this 3 times and the contents are still lost            // assume we're painting to a VolatileImage that is bogus and            // give up.  Presumably we'll be called again to paint.        } while ((image instanceof VolatileImage) &&                 ((VolatileImage)image).contentsLost() && ++attempts < 3);    }     /**     * Paints the representation to cache to the supplied Graphics.     *     * @param c Component painting to, may be null.     * @param image Image to paint to     * @param g Graphics to paint to, obtained from the passed in Image.     * @param w Width to paint to     * @param h Height to paint to     * @param args Arguments supplied to <code>paint</code>     */    protected abstract void paintToImage(Component c, Image image, Graphics g,                                         int w, int h, Object[] args);      /**     * Paints the image to the specified location.     *     * @param c Component painting to     * @param g Graphics to paint to     * @param x X coordinate to paint to     * @param y Y coordinate to paint to     * @param w Width to paint to     * @param h Height to paint to     * @param image Image to paint     * @param args Arguments supplied to <code>paint</code>     */    protected void paintImage(Component c, Graphics g,                              int x, int y, int w, int h, Image image,                              Object[] args) {        g.drawImage(image, x, y, null);    }     /**     * Creates the image to cache.  This returns an opaque image, subclasses     * that require translucency or transparency will need to override this     * method.     *     * @param c Component painting to     * @param w Width of image to create     * @param h Height to image to create     * @param config GraphicsConfiguration that will be     *        rendered to, this may be null.     * @param args Arguments passed to paint     */    protected Image createImage(Component c, int w, int h,                                GraphicsConfiguration config, Object[] args) {        if (config == null) {            return new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);        }        return config.createCompatibleVolatileImage(w, h);    }     /**     * Clear the image cache     */    protected void flush() {        synchronized(CachedPainter.class) {            getCache(getClass()).flush();        }    }     private GraphicsConfiguration getGraphicsConfiguration(Component c) {        if (c == null) {            return null;        }        return c.getGraphicsConfiguration();    }}