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 }