Module java.desktop

Package java.awt

Class Component.BltBufferStrategy

java.lang.Object

java.awt.image.BufferStrategy

java.awt.Component.BltBufferStrategy

Enclosing class:

Component

protected class Component.BltBufferStrategy
extends BufferStrategy

Inner class for blitting offscreen surfaces to a component.

Since:

1.4

Field Summary

Fields

Modifier and Type	Field	Description
protected VolatileImage[]	backBuffers	The back buffers
protected BufferCapabilities	caps	The buffering capabilities
protected int	height	Height of the back buffers
protected boolean	validatedContents	Whether or not the drawing buffer has been recently restored from a lost state.
protected int	width	Width of the back buffers

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BltBufferStrategy(int numBuffers, BufferCapabilities caps)	Creates a new blt buffer strategy around a component

Method Summary

Modifier and Type	Method	Description
boolean	contentsLost()	Returns whether the drawing buffer was lost since the last call to getDrawGraphics.
boolean	contentsRestored()	Returns whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white).
protected void	createBackBuffers(int numBuffers)	Creates the back buffers
void	dispose()	Releases system resources currently consumed by this BufferStrategy and removes it from the associated Component.
BufferCapabilities	getCapabilities()	Returns the BufferCapabilities for this BufferStrategy.
Graphics	getDrawGraphics()	Creates a graphics context for the drawing buffer.
protected void	revalidate()	Restore the drawing buffer if it has been lost
void	show()	Makes the next available buffer visible.

Methods declared in class java.lang.Object

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

Field Details

caps

protected BufferCapabilities caps

The buffering capabilities

backBuffers

protected VolatileImage[] backBuffers

The back buffers

validatedContents

protected boolean validatedContents

Whether or not the drawing buffer has been recently restored from a lost state.

width

protected int width

Width of the back buffers

height

protected int height

Height of the back buffers

Constructor Details

BltBufferStrategy

protected BltBufferStrategy(int numBuffers,
 BufferCapabilities caps)

Creates a new blt buffer strategy around a component

Parameters:

numBuffers - number of buffers to create, including the front buffer

caps - the capabilities of the buffers

Method Details

dispose

public void dispose()

Releases system resources currently consumed by this BufferStrategy and removes it from the associated Component. After invoking this method, getBufferStrategy will return null. Trying to use a BufferStrategy after it has been disposed will result in undefined behavior.

Overrides:

dispose in class BufferStrategy

Since:

1.6

See Also:

• Window.createBufferStrategy(int)
• Canvas.createBufferStrategy(int)
• Window.getBufferStrategy()
• Canvas.getBufferStrategy()

createBackBuffers

protected void createBackBuffers(int numBuffers)

Creates the back buffers

Parameters:

numBuffers - the number of buffers to create

getCapabilities

public BufferCapabilities getCapabilities()

Description copied from class: BufferStrategy

Returns the BufferCapabilities for this BufferStrategy.

Specified by:

getCapabilities in class BufferStrategy

Returns:

the buffering capabilities of this strategy

getDrawGraphics

public Graphics getDrawGraphics()

Description copied from class: BufferStrategy

Creates a graphics context for the drawing buffer. This method may not be synchronized for performance reasons; use of this method by multiple threads should be handled at the application level. Disposal of the graphics object obtained must be handled by the application.

Specified by:

getDrawGraphics in class BufferStrategy

Returns:

the draw graphics

show

public void show()

Makes the next available buffer visible.

Specified by:

show in class BufferStrategy

revalidate

protected void revalidate()

Restore the drawing buffer if it has been lost

contentsLost

public boolean contentsLost()

Description copied from class: BufferStrategy

Returns whether the drawing buffer was lost since the last call to getDrawGraphics. Since the buffers in a buffer strategy are usually type VolatileImage, they may become lost. For a discussion on lost buffers, see VolatileImage.

Specified by:

contentsLost in class BufferStrategy

Returns:

whether the drawing buffer was lost since the last call to getDrawGraphics

See Also:

• VolatileImage

contentsRestored

public boolean contentsRestored()

Description copied from class: BufferStrategy

Returns whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white). Since the buffers in a buffer strategy are usually type VolatileImage, they may become lost. If a surface has been recently restored from a lost state since the last call to getDrawGraphics, it may require repainting. For a discussion on lost buffers, see VolatileImage.

Specified by:

contentsRestored in class BufferStrategy

Returns:

whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white)

See Also:

• VolatileImage