Component.BltBufferStrategy (Java SE 17 & JDK 17)
Description: declaration: module: java.desktop, package: java.awt, class: Component, class: BltBufferStrategy
Keywords: java.awt.Component.BltBufferStrategy class

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`