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Interface java.awt.image.WritableRenderedImage

public interface WritableRenderedImage
extends RenderedImage
WriteableRenderedImage is a common interface for objects which contain or can produce image data which can be modified and/or written over. WritableRenderedImage provides notification to other interested objects when a tile is checked out for writing (via the getWritableTile method) and when the last writer of a particular tile relinquishes its access (via a call to releaseWritableTile). Additionally, it allows any caller to determine whether any tiles are currently checked out (via hasTileWriters), and to obtain a list of such tiles (from getWritableTiles, in the form of a Vector of Point objects). Object wishing to be notified of changes in tile writability must implement the TileChangeListener interface, and are added by a call to addTileChangeListener. Multiple calls to addTileChangeListener for the same object will result in multiple notifications. An existing listener may reduce its notifications by calling removeTileChangeListener; if the listener had no notifications the operation is a no-op. A Vector of the current TileChangeListeners is obtained by calling getTileChangeListeners. It is necessary for a WritableRenderedImage to ensure that notifications occur only when the first writer acquires a tile and the last writer deacquires it. To simplify the necessary bookkeeping, the TileChangeMulticaster class is available. Calls to getWritableTile are forwarded to calls to addTileWriter and calls to releaseWritableTile are forwared to calls to removeTileWriter; other listener-related calls are trivially forwarded (see BufferedImage for an example of this style of implementation). A TileChangeMulticaster may be used to inform a number of objects of a tile change event from a single notification.

Method Index

o addTileChangeListener(TileChangeListener)
Add a listener.
o getTileChangeListeners()
Return a Vector of TileChangeListener objects.
o getWritableTile(int, int)
Check out a tile for writing.
o getWritableTiles()
Return a array of Point objects indicating which tiles are checked out for writing.
o hasTileWriters()
Return whether any tile is checked out for writing.
o isTileWritable(int, int)
Return whether a tile is currently checked out for writing.
o releaseWritableTile(int, int)
Relinquish the right to write to a tile.
o removeTileChangeListener(TileChangeListener)
Remove a listener.
o setRect(Raster)
Set a rect of the image to the contents of rb.

Methods

o addTileChangeListener 
public abstract void addTileChangeListener(TileChangeListener tcl)
Add a listener. If the listener is already present, it will receive multiple notifications.

o removeTileChangeListener 
public abstract void removeTileChangeListener(TileChangeListener tcl)
Remove a listener. If the listener was not registered, nothing happens. If the listener was registered for multiple notifications, it will now be registered for one fewer.

o getTileChangeListeners 
public abstract TileChangeListener[] getTileChangeListeners()
Return a Vector of TileChangeListener objects. Listeners registered multiple times will appear a corresponding number of times in the list.

o getWritableTile 
public abstract WritableRaster getWritableTile(int tileX,
                                               int tileY)
Check out a tile for writing. This method is already part of the WritableRenderedImage interface. The WritableRenderedImage is responsible for notifying all of its TileChangeListeners when a tile goes from having no writers to having one writer. A simple way to fulfill this contract is to instantiate a TileChangeFilter and to call its addTileWriter method every time this method is called.

Parameters:
tileX - the X index of the tile.
tileY - the Y index of the tile.
o releaseWritableTile 
public abstract void releaseWritableTile(int tileX,
                                         int tileY)
Relinquish the right to write to a tile. If the caller continues to write to the tile, the results are undefined. Calls to his method should only appear in matching pairs with calls to getWritableTile; any other use will lead to undefined results. The WritableRenderedImage is responsible for notifying all of its TileChangeListeners when a tile goes from having one writer to having no writers. A simple way to fulfill this contract is to instantiate a TileChangeFilter and to call its removeTileWriter method every time this method is called.

Parameters:
tileX - the X index of the tile.
tileY - the Y index of the tile.
o isTileWritable 
public abstract boolean isTileWritable(int tileX,
                                       int tileY)
Return whether a tile is currently checked out for writing. This may be implemented by delegation to a TileChangeFilter.

Parameters:
tileX - the X index of the tile.
tileY - the Y index of the tile.
o getWritableTiles 
public abstract Point[] getWritableTiles()
Return a array of Point objects indicating which tiles are checked out for writing.

o hasTileWriters 
public abstract boolean hasTileWriters()
Return whether any tile is checked out for writing. Equivalent to (getWritableTiles().size() != 0).

o setRect 
public abstract void setRect(Raster rb)
Set a rect of the image to the contents of rb. 

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