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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/awt/image/BufferStrategy.java | |
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Diffstat (limited to 'libjava/classpath/java/awt/image/BufferStrategy.java')
-rw-r--r-- | libjava/classpath/java/awt/image/BufferStrategy.java | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/libjava/classpath/java/awt/image/BufferStrategy.java b/libjava/classpath/java/awt/image/BufferStrategy.java new file mode 100644 index 000000000..e86aad60f --- /dev/null +++ b/libjava/classpath/java/awt/image/BufferStrategy.java @@ -0,0 +1,124 @@ +/* BufferStrategy.java -- describes image buffering resources + Copyright (C) 2002, 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.awt.image; + +import java.awt.BufferCapabilities; +import java.awt.Graphics; + +/** + * This class describes a strategy for managing image buffering + * resources on a Canvas or Window. A given buffer strategy may make + * use of hardware acceleration or take advantage of features of the + * native graphics system. Examples of buffering strategies are + * double or triple buffering using either flipping or blitting. For + * the details of these algorithms see BufferCapabilities. + * + * To use a buffer strategy, you retrieve it from either the current + * GraphicsConfiguration or from the Component on which you'd like to + * draw. Then you can query the strategy's capabilities to make sure + * they're suitable. + * + * If the strategy's capabilities are suitable, you can obtain a + * graphics object and use it to draw with this strategy. Drawing + * with a buffer strategy requires extra care, however. You'll need + * to manually cause the next buffer to be shown on the output device. + * And since buffer strategies are usually implemented with a + * VolatileImage, you must frequently check that the contents of the + * buffer are valid and that the buffer still exists. + * + * A buffer strategy is usually implemented using a VolatileImage. + * + * @see VolatileImage + * @since 1.4 + */ +public abstract class BufferStrategy +{ + /** + * Creates a new buffer strategy. + */ + public BufferStrategy() + { + } + + /** + * Retrieves the capabilities of this buffer strategy. + * + * @return this buffer strategy's capabilities + */ + public abstract BufferCapabilities getCapabilities(); + + /** + * Retrieves a graphics object that can be used to draw using this + * buffer strategy. This method may not be synchronized so be + * careful when calling it from multiple threads. You also must + * manually dispose of this graphics object. + * + * @return a graphics object that can be used to draw using this + * buffer strategy + */ + public abstract Graphics getDrawGraphics(); + + /** + * Returns whether or not the buffer's resources have been reclaimed + * by the native graphics system. If the buffer resources have been + * lost then you'll need to obtain new resources before drawing + * again. For details, see the documentation for VolatileImage. + * + * @return true if the contents were lost, false otherwise + */ + public abstract boolean contentsLost(); + + /** + * Returns whether or not the buffer's resources were re-created and + * cleared to the default background color. If the buffer's + * resources have recently been re-created and initialized then the + * buffer's image may need to be re-rendered. For details, see the + * documentation for VolatileImage. + * + * @return true if the contents were restored, false otherwise + */ + public abstract boolean contentsRestored(); + + /** + * Applies this buffer strategy. In other words, this method brings + * the contents of the back or intermediate buffers to the front + * buffer. + */ + public abstract void show(); +} |