1 /* 2 * Copyright (c) 2004, 2006, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package sun.swing; 26 27 import java.awt.*; 28 import java.awt.image.*; 29 import java.util.*; 30 31 /** 32 * A base class used for icons or images that are expensive to paint. 33 * A subclass will do the following: 34 * <ol> 35 * <li>Invoke <code>paint</code> when you want to paint the image, 36 * if you are implementing <code>Icon</code> you'll invoke this from 37 * <code>paintIcon</code>. 38 * The args argument is useful when additional state is needed. 39 * <li>Override <code>paintToImage</code> to render the image. The code that 40 * lives here is equivalent to what previously would go in 41 * <code>paintIcon</code>, for an <code>Icon</code>. 42 * </ol> 43 * The two ways to use this class are: 44 * <ol> 45 * <li>Invoke <code>paint</code> to draw the cached reprensentation at 46 * the specified location. 47 * <li>Invoke <code>getImage</code> to get the cached reprensentation and 48 * draw the image yourself. This is primarly useful when you are not 49 * using <code>VolatileImage</code>. 50 * </ol> 51 * 52 * 53 */ 54 public abstract class CachedPainter { 55 // CacheMap maps from class to ImageCache. 56 private static final Map<Object,ImageCache> cacheMap = 57 new HashMap<Object,ImageCache>(); 58 59 60 private static ImageCache getCache(Object key) { 61 synchronized(CachedPainter.class) { 62 ImageCache cache = cacheMap.get(key); 63 if (cache == null) { 64 cache = new ImageCache(1); 65 cacheMap.put(key, cache); 66 } 67 return cache; 68 } 69 } 70 71 /** 72 * Creates an instance of <code>CachedPainter</code> that will cache up 73 * to <code>cacheCount</code> images of this class. 74 * 75 * @param cacheCount Max number of images to cache 76 */ 77 public CachedPainter(int cacheCount) { 78 getCache(getClass()).setMaxCount(cacheCount); 79 } 80 81 /** 82 * Renders the cached image to the passed in <code>Graphic</code>. 83 * If there is no cached image <code>paintToImage</code> will be invoked. 84 * <code>paintImage</code> is invoked to paint the cached image. 85 * 86 * @param c Component rendering to, this may be null. 87 * @param g Graphics to paint to 88 * @param x X-coordinate to render to 89 * @param y Y-coordinate to render to 90 * @param w Width to render in 91 * @param h Height to render in 92 * @param args Variable arguments that will be passed to paintToImage 93 */ 94 public void paint(Component c, Graphics g, int x, 95 int y, int w, int h, Object... args) { 96 if (w <= 0 || h <= 0) { 97 return; 98 } 99 if (c != null) { 100 synchronized(c.getTreeLock()) { 101 synchronized(CachedPainter.class) { 102 // If c is non-null, synchronize on the tree lock. 103 // This is necessary because asking for the 104 // GraphicsConfiguration will grab a tree lock. 105 paint0(c, g, x, y, w, h, args); 106 } 107 } 108 } 109 else { 110 synchronized(CachedPainter.class) { 111 paint0(c, g, x, y, w, h, args); 112 } 113 } 114 } 115 116 private void paint0(Component c, Graphics g, int x, 117 int y, int w, int h, Object... args) { 118 Object key = getClass(); 119 GraphicsConfiguration config = getGraphicsConfiguration(c); 120 ImageCache cache = getCache(key); 121 Image image = cache.getImage(key, config, w, h, args); 122 int attempts = 0; 123 do { 124 boolean draw = false; 125 if (image instanceof VolatileImage) { 126 // See if we need to recreate the image 127 switch (((VolatileImage)image).validate(config)) { 128 case VolatileImage.IMAGE_INCOMPATIBLE: 129 ((VolatileImage)image).flush(); 130 image = null; 131 break; 132 case VolatileImage.IMAGE_RESTORED: 133 draw = true; 134 break; 135 } 136 } 137 if (image == null) { 138 // Recreate the image 139 image = createImage(c, w, h, config, args); 140 cache.setImage(key, config, w, h, args, image); 141 draw = true; 142 } 143 if (draw) { 144 // Render to the Image 145 Graphics g2 = image.getGraphics(); 146 paintToImage(c, image, g2, w, h, args); 147 g2.dispose(); 148 } 149 150 // Render to the passed in Graphics 151 paintImage(c, g, x, y, w, h, image, args); 152 153 // If we did this 3 times and the contents are still lost 154 // assume we're painting to a VolatileImage that is bogus and 155 // give up. Presumably we'll be called again to paint. 156 } while ((image instanceof VolatileImage) && 157 ((VolatileImage)image).contentsLost() && ++attempts < 3); 158 } 159 160 /** 161 * Paints the representation to cache to the supplied Graphics. 162 * 163 * @param c Component painting to, may be null. 164 * @param image Image to paint to 165 * @param g Graphics to paint to, obtained from the passed in Image. 166 * @param w Width to paint to 167 * @param h Height to paint to 168 * @param args Arguments supplied to <code>paint</code> 169 */ 170 protected abstract void paintToImage(Component c, Image image, Graphics g, 171 int w, int h, Object[] args); 172 173 174 /** 175 * Paints the image to the specified location. 176 * 177 * @param c Component painting to 178 * @param g Graphics to paint to 179 * @param x X coordinate to paint to 180 * @param y Y coordinate to paint to 181 * @param w Width to paint to 182 * @param h Height to paint to 183 * @param image Image to paint 184 * @param args Arguments supplied to <code>paint</code> 185 */ 186 protected void paintImage(Component c, Graphics g, 187 int x, int y, int w, int h, Image image, 188 Object[] args) { 189 g.drawImage(image, x, y, null); 190 } 191 192 /** 193 * Creates the image to cache. This returns an opaque image, subclasses 194 * that require translucency or transparency will need to override this 195 * method. 196 * 197 * @param c Component painting to 198 * @param w Width of image to create 199 * @param h Height to image to create 200 * @param config GraphicsConfiguration that will be 201 * rendered to, this may be null. 202 * @param args Arguments passed to paint 203 */ 204 protected Image createImage(Component c, int w, int h, 205 GraphicsConfiguration config, Object[] args) { 206 if (config == null) { 207 return new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 208 } 209 return config.createCompatibleVolatileImage(w, h); 210 } 211 212 /** 213 * Clear the image cache 214 */ 215 protected void flush() { 216 synchronized(CachedPainter.class) { 217 getCache(getClass()).flush(); 218 } 219 } 220 221 private GraphicsConfiguration getGraphicsConfiguration(Component c) { 222 if (c == null) { 223 return null; 224 } 225 return c.getGraphicsConfiguration(); 226 } 227 }