java.awt.image
Class BufferStrategy
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.
abstract boolean | contentsLost()- Returns whether or not the buffer's resources have been reclaimed
by the native graphics system.
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abstract boolean | contentsRestored()- Returns whether or not the buffer's resources were re-created and
cleared to the default background color.
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abstract BufferCapabilities | getCapabilities()- Retrieves the capabilities of this buffer strategy.
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abstract Graphics | getDrawGraphics()- Retrieves a graphics object that can be used to draw using this
buffer strategy.
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abstract void | show()- Applies this buffer strategy.
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clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
contentsLost
public abstract boolean contentsLost()
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.
- true if the contents were lost, false otherwise
contentsRestored
public abstract boolean contentsRestored()
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.
- true if the contents were restored, false otherwise
getDrawGraphics
public abstract Graphics getDrawGraphics()
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.
- a graphics object that can be used to draw using this
buffer strategy
show
public abstract void show()
Applies this buffer strategy. In other words, this method brings
the contents of the back or intermediate buffers to the front
buffer.
BufferStrategy.java -- describes image buffering resources
Copyright (C) 2002, 2005 Free Software Foundation, Inc.
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