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 }