java.awt.image

Class BufferStrategy

java.lang.Object

java.awt.image.BufferStrategy

public abstract class BufferStrategy
extends java.lang.Object

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.

Since:

1.4

See Also:

VolatileImage

Constructor Summary

Constructors

Constructor and Description
BufferStrategy() Creates a new buffer strategy.

Method Summary

Methods

Modifier and Type	Method and Description
abstract boolean	contentsLost() Returns whether or not the buffer's resources have been reclaimed by the native graphics system.
abstract boolean	contentsRestored() Returns whether or not the buffer's resources were re-created and cleared to the default background color.
abstract java.awt.BufferCapabilities	getCapabilities() Retrieves the capabilities of this buffer strategy.
abstract java.awt.Graphics	getDrawGraphics() Retrieves a graphics object that can be used to draw using this buffer strategy.
abstract void	show() Applies this buffer strategy.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BufferStrategy

public BufferStrategy()

Creates a new buffer strategy.

Method Detail

getCapabilities

public abstract java.awt.BufferCapabilities getCapabilities()

Retrieves the capabilities of this buffer strategy.

Returns:

this buffer strategy's capabilities

getDrawGraphics

public abstract java.awt.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.

Returns:

a graphics object that can be used to draw using this buffer strategy

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.

Returns:

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.

Returns:

true if the contents were restored, false otherwise

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.