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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package sun.swing;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
/**
* A base class used for icons or images that are expensive to paint.
* A subclass will do the following:
* <ol>
* <li>Invoke <code>paint</code> when you want to paint the image,
* if you are implementing <code>Icon</code> you'll invoke this from
* <code>paintIcon</code>.
* The args argument is useful when additional state is needed.
* <li>Override <code>paintToImage</code> to render the image. The code that
* lives here is equivalent to what previously would go in
* <code>paintIcon</code>, for an <code>Icon</code>.
* </ol>
* The two ways to use this class are:
* <ol>
* <li>Invoke <code>paint</code> to draw the cached reprensentation at
* the specified location.
* <li>Invoke <code>getImage</code> to get the cached reprensentation and
* draw the image yourself. This is primarly useful when you are not
* using <code>VolatileImage</code>.
* </ol>
*
*
*/
public abstract class CachedPainter {
// CacheMap maps from class to ImageCache.
private static final Map<Object,ImageCache> cacheMap =
new HashMap<Object,ImageCache>();
private static ImageCache getCache(Object key) {
synchronized(CachedPainter.class) {
ImageCache cache = cacheMap.get(key);
if (cache == null) {
cache = new ImageCache(1);
cacheMap.put(key, cache);
}
return cache;
}
}
/**
* Creates an instance of <code>CachedPainter</code> that will cache up
* to <code>cacheCount</code> images of this class.
*
* @param cacheCount Max number of images to cache
*/
public CachedPainter(int cacheCount) {
getCache(getClass()).setMaxCount(cacheCount);
}
/**
* Renders the cached image to the the passed in <code>Graphic</code>.
* If there is no cached image <code>paintToImage</code> will be invoked.
* <code>paintImage</code> is invoked to paint the cached image.
*
* @param c Component rendering to, this may be null.
* @param g Graphics to paint to
* @param x X-coordinate to render to
* @param y Y-coordinate to render to
* @param w Width to render in
* @param h Height to render in
* @param arg Variable arguments that will be passed to paintToImage
*/
public void paint(Component c, Graphics g, int x,
int y, int w, int h, Object... args) {
if (w <= 0 || h <= 0) {
return;
}
if (c != null) {
synchronized(c.getTreeLock()) {
synchronized(CachedPainter.class) {
// If c is non-null, synchronize on the tree lock.
// This is necessary because asking for the
// GraphicsConfiguration will grab a tree lock.
paint0(c, g, x, y, w, h, args);
}
}
}
else {
synchronized(CachedPainter.class) {
paint0(c, g, x, y, w, h, args);
}
}
}
private void paint0(Component c, Graphics g, int x,
int y, int w, int h, Object... args) {
Object key = getClass();
GraphicsConfiguration config = getGraphicsConfiguration(c);
ImageCache cache = getCache(key);
Image image = cache.getImage(key, config, w, h, args);
int attempts = 0;
do {
boolean draw = false;
if (image instanceof VolatileImage) {
// See if we need to recreate the image
switch (((VolatileImage)image).validate(config)) {
case VolatileImage.IMAGE_INCOMPATIBLE:
((VolatileImage)image).flush();
image = null;
break;
case VolatileImage.IMAGE_RESTORED:
draw = true;
break;
}
}
if (image == null) {
// Recreate the image
image = createImage(c, w, h, config, args);
cache.setImage(key, config, w, h, args, image);
draw = true;
}
if (draw) {
// Render to the Image
Graphics g2 = image.getGraphics();
paintToImage(c, image, g2, w, h, args);
g2.dispose();
}
// Render to the passed in Graphics
paintImage(c, g, x, y, w, h, image, args);
// If we did this 3 times and the contents are still lost
// assume we're painting to a VolatileImage that is bogus and
// give up. Presumably we'll be called again to paint.
} while ((image instanceof VolatileImage) &&
((VolatileImage)image).contentsLost() && ++attempts < 3);
}
/**
* Paints the representation to cache to the supplied Graphics.
*
* @param c Component painting to, may be null.
* @param image Image to paint to
* @param g Graphics to paint to, obtained from the passed in Image.
* @param w Width to paint to
* @param h Height to paint to
* @param args Arguments supplied to <code>paint</code>
*/
protected abstract void paintToImage(Component c, Image image, Graphics g,
int w, int h, Object[] args);
/**
* Paints the image to the specified location.
*
* @param c Component painting to
* @param g Graphics to paint to
* @param x X coordinate to paint to
* @param y Y coordinate to paint to
* @param w Width to paint to
* @param h Height to paint to
* @param image Image to paint
* @param args Arguments supplied to <code>paint</code>
*/
protected void paintImage(Component c, Graphics g,
int x, int y, int w, int h, Image image,
Object[] args) {
g.drawImage(image, x, y, null);
}
/**
* Creates the image to cache. This returns an opaque image, subclasses
* that require translucency or transparency will need to override this
* method.
*
* @param c Component painting to
* @param w Width of image to create
* @param h Height to image to create
* @param config GraphicsConfiguration that will be
* rendered to, this may be null.
* @param args Arguments passed to paint
*/
protected Image createImage(Component c, int w, int h,
GraphicsConfiguration config, Object[] args) {
if (config == null) {
return new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
}
return config.createCompatibleVolatileImage(w, h);
}
/**
* Clear the image cache
*/
protected void flush() {
synchronized(CachedPainter.class) {
getCache(getClass()).flush();
}
}
private GraphicsConfiguration getGraphicsConfiguration(Component c) {
if (c == null) {
return null;
}
return c.getGraphicsConfiguration();
}
}