1 /* 2 * Copyright (c) 2004, 2015, 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 = new HashMap<>(); 57 58 private static ImageCache getCache(Object key) { 59 synchronized(CachedPainter.class) { 60 ImageCache cache = cacheMap.get(key); 61 if (cache == null) { 62 cache = new ImageCache(1); 63 cacheMap.put(key, cache); 64 } 65 return cache; 66 } 67 } 68 69 /** 70 * Creates an instance of <code>CachedPainter</code> that will cache up 71 * to <code>cacheCount</code> images of this class. 72 * 73 * @param cacheCount Max number of images to cache 74 */ 75 public CachedPainter(int cacheCount) { 76 getCache(getClass()).setMaxCount(cacheCount); 77 } 78 79 /** 80 * Renders the cached image to the passed in <code>Graphic</code>. 81 * If there is no cached image <code>paintToImage</code> will be invoked. 82 * <code>paintImage</code> is invoked to paint the cached image. 83 * 84 * @param c Component rendering to, this may be null. 85 * @param g Graphics to paint to 86 * @param x X-coordinate to render to 87 * @param y Y-coordinate to render to 88 * @param w Width to render in 89 * @param h Height to render in 90 * @param args Variable arguments that will be passed to paintToImage 91 */ 92 public void paint(Component c, Graphics g, int x, 93 int y, int w, int h, Object... args) { 94 if (w <= 0 || h <= 0) { 95 return; 96 } 97 synchronized (CachedPainter.class) { 98 paint0(c, g, x, y, w, h, args); 99 } 100 } 101 102 private void paint0(Component c, Graphics g, int x, 103 int y, int w, int h, Object... args) { 104 Object key = getClass(); 105 GraphicsConfiguration config = getGraphicsConfiguration(c); 106 ImageCache cache = getCache(key); 107 Image image = cache.getImage(key, config, w, h, args); 108 int attempts = 0; 109 do { 110 boolean draw = false; 111 if (image instanceof VolatileImage) { 112 // See if we need to recreate the image 113 switch (((VolatileImage)image).validate(config)) { 114 case VolatileImage.IMAGE_INCOMPATIBLE: 115 ((VolatileImage)image).flush(); 116 image = null; 117 break; 118 case VolatileImage.IMAGE_RESTORED: 119 draw = true; 120 break; 121 } 122 } 123 if (image == null) { 124 // Recreate the image 125 image = createImage(c, w, h, config, args); 126 cache.setImage(key, config, w, h, args, image); 127 draw = true; 128 } 129 if (draw) { 130 // Render to the Image 131 Graphics g2 = image.getGraphics(); 132 paintToImage(c, image, g2, w, h, args); 133 g2.dispose(); 134 } 135 136 // Render to the passed in Graphics 137 paintImage(c, g, x, y, w, h, image, args); 138 139 // If we did this 3 times and the contents are still lost 140 // assume we're painting to a VolatileImage that is bogus and 141 // give up. Presumably we'll be called again to paint. 142 } while ((image instanceof VolatileImage) && 143 ((VolatileImage)image).contentsLost() && ++attempts < 3); 144 } 145 146 /** 147 * Paints the representation to cache to the supplied Graphics. 148 * 149 * @param c Component painting to, may be null. 150 * @param image Image to paint to 151 * @param g Graphics to paint to, obtained from the passed in Image. 152 * @param w Width to paint to 153 * @param h Height to paint to 154 * @param args Arguments supplied to <code>paint</code> 155 */ 156 protected abstract void paintToImage(Component c, Image image, Graphics g, 157 int w, int h, Object[] args); 158 159 160 /** 161 * Paints the image to the specified location. 162 * 163 * @param c Component painting to 164 * @param g Graphics to paint to 165 * @param x X coordinate to paint to 166 * @param y Y coordinate to paint to 167 * @param w Width to paint to 168 * @param h Height to paint to 169 * @param image Image to paint 170 * @param args Arguments supplied to <code>paint</code> 171 */ 172 protected void paintImage(Component c, Graphics g, 173 int x, int y, int w, int h, Image image, 174 Object[] args) { 175 g.drawImage(image, x, y, null); 176 } 177 178 /** 179 * Creates the image to cache. This returns an opaque image, subclasses 180 * that require translucency or transparency will need to override this 181 * method. 182 * 183 * @param c Component painting to 184 * @param w Width of image to create 185 * @param h Height to image to create 186 * @param config GraphicsConfiguration that will be 187 * rendered to, this may be null. 188 * @param args Arguments passed to paint 189 */ 190 protected Image createImage(Component c, int w, int h, 191 GraphicsConfiguration config, Object[] args) { 192 if (config == null) { 193 return new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 194 } 195 return config.createCompatibleVolatileImage(w, h); 196 } 197 198 /** 199 * Clear the image cache 200 */ 201 protected void flush() { 202 synchronized(CachedPainter.class) { 203 getCache(getClass()).flush(); 204 } 205 } 206 207 private GraphicsConfiguration getGraphicsConfiguration(Component c) { 208 if (c == null) { 209 return null; 210 } 211 return c.getGraphicsConfiguration(); 212 } 213 }