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.geom.AffineTransform;
29 import java.awt.image.*;
30 import java.util.*;
31
32 /**
33 * A base class used for icons or images that are expensive to paint.
34 * A subclass will do the following:
35 * <ol>
36 * <li>Invoke <code>paint</code> when you want to paint the image,
37 * if you are implementing <code>Icon</code> you'll invoke this from
38 * <code>paintIcon</code>.
39 * The args argument is useful when additional state is needed.
40 * <li>Override <code>paintToImage</code> to render the image. The code that
41 * lives here is equivalent to what previously would go in
42 * <code>paintIcon</code>, for an <code>Icon</code>.
43 * </ol>
44 * The two ways to use this class are:
45 * <ol>
46 * <li>Invoke <code>paint</code> to draw the cached reprensentation at
47 * the specified location.
48 * <li>Invoke <code>getImage</code> to get the cached reprensentation and
49 * draw the image yourself. This is primarly useful when you are not
50 * using <code>VolatileImage</code>.
51 * </ol>
52 *
53 *
54 */
55 public abstract class CachedPainter {
56 // CacheMap maps from class to ImageCache.
57 private static final Map<Object,ImageCache> cacheMap = new HashMap<>();
58
59 private static ImageCache getCache(Object key) {
60 synchronized(CachedPainter.class) {
61 ImageCache cache = cacheMap.get(key);
62 if (cache == null) {
63 cache = new ImageCache(1);
64 cacheMap.put(key, cache);
65 }
66 return cache;
67 }
68 }
69
70 /**
71 * Creates an instance of <code>CachedPainter</code> that will cache up
72 * to <code>cacheCount</code> images of this class.
73 *
74 * @param cacheCount Max number of images to cache
75 */
76 public CachedPainter(int cacheCount) {
77 getCache(getClass()).setMaxCount(cacheCount);
78 }
79
80 /**
81 * Renders the cached image to the passed in <code>Graphic</code>.
82 * If there is no cached image <code>paintToImage</code> will be invoked.
83 * <code>paintImage</code> is invoked to paint the cached image.
84 *
85 * @param c Component rendering to, this may be null.
86 * @param g Graphics to paint to
87 * @param x X-coordinate to render to
88 * @param y Y-coordinate to render to
89 * @param w Width to render in
90 * @param h Height to render in
91 * @param args Variable arguments that will be passed to paintToImage
92 */
93 public void paint(Component c, Graphics g, int x,
94 int y, int w, int h, Object... args) {
95 if (w <= 0 || h <= 0) {
96 return;
97 }
98 synchronized (CachedPainter.class) {
99 paint0(c, g, x, y, w, h, args);
100 }
101 }
102
103 private void paint0(Component c, Graphics g, int x,
104 int y, int w, int h, Object... args) {
105 Object key = getClass();
106 GraphicsConfiguration config = getGraphicsConfiguration(c);
107 ImageCache cache = getCache(key);
108
109 AffineTransform tx = ((Graphics2D) g).getTransform();
110 int sw = tx.isIdentity() ? w : (int) Math.round(w * tx.getScaleX());
111 int sh = tx.isIdentity() ? h : (int) Math.round(h * tx.getScaleY());
112
113 Image image = cache.getImage(key, config, sw, sh, args);
114 int attempts = 0;
115 do {
116 boolean draw = false;
117 if (image instanceof VolatileImage) {
118 // See if we need to recreate the image
119 switch (((VolatileImage)image).validate(config)) {
120 case VolatileImage.IMAGE_INCOMPATIBLE:
121 ((VolatileImage)image).flush();
122 image = null;
123 break;
124 case VolatileImage.IMAGE_RESTORED:
125 draw = true;
126 break;
127 }
128 }
129 if (image == null) {
130 // Recreate the image
131 image = createImage(c, sw, sh, config, args);
132 cache.setImage(key, config, sw, sh, args, image);
133 draw = true;
134 }
135 if (draw) {
136 // Render to the Image
137 Graphics g2 = image.getGraphics();
138 paintToImage(c, image, g2, sw, sh, args);
139 g2.dispose();
140 }
141
142 // Render to the passed in Graphics
143 paintImage(c, g, x, y, w, h, image, args);
144
145 // If we did this 3 times and the contents are still lost
146 // assume we're painting to a VolatileImage that is bogus and
147 // give up. Presumably we'll be called again to paint.
148 } while ((image instanceof VolatileImage) &&
149 ((VolatileImage)image).contentsLost() && ++attempts < 3);
150 }
151
152 /**
153 * Paints the representation to cache to the supplied Graphics.
154 *
155 * @param c Component painting to, may be null.
156 * @param image Image to paint to
157 * @param g Graphics to paint to, obtained from the passed in Image.
158 * @param w Width to paint to
159 * @param h Height to paint to
160 * @param args Arguments supplied to <code>paint</code>
161 */
162 protected abstract void paintToImage(Component c, Image image, Graphics g,
163 int w, int h, Object[] args);
164
165
166 /**
167 * Paints the image to the specified location.
168 *
169 * @param c Component painting to
170 * @param g Graphics to paint to
171 * @param x X coordinate to paint to
172 * @param y Y coordinate to paint to
173 * @param w Width to paint to
174 * @param h Height to paint to
175 * @param image Image to paint
176 * @param args Arguments supplied to <code>paint</code>
177 */
178 protected void paintImage(Component c, Graphics g,
179 int x, int y, int w, int h, Image image,
180 Object[] args) {
181 g.drawImage(image, x, y, w, h, null);
182 }
183
184 /**
185 * Creates the image to cache. This returns an opaque image, subclasses
186 * that require translucency or transparency will need to override this
187 * method.
188 *
189 * @param c Component painting to
190 * @param w Width of image to create
191 * @param h Height to image to create
192 * @param config GraphicsConfiguration that will be
193 * rendered to, this may be null.
194 * @param args Arguments passed to paint
195 */
196 protected Image createImage(Component c, int w, int h,
197 GraphicsConfiguration config, Object[] args) {
198 if (config == null) {
199 return new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
200 }
201 return config.createCompatibleVolatileImage(w, h);
202 }
203
204 /**
205 * Clear the image cache
206 */
207 protected void flush() {
208 synchronized(CachedPainter.class) {
209 getCache(getClass()).flush();
210 }
211 }
212
213 private GraphicsConfiguration getGraphicsConfiguration(Component c) {
214 if (c == null) {
215 return null;
216 }
217 return c.getGraphicsConfiguration();
218 }
219 }