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 (via getWritableTileIndices, in the form of a Vector of Point objects).
Objects wishing to be notified of changes in tile writability must implement the TileObserver interface, and are added by a call to addTileObserver. Multiple calls to addTileObserver for the same object will result in multiple notifications. An existing observer may reduce its notifications by calling removeTileObserver; if the observer had no notifications the operation is a no-op.
It is necessary for a WritableRenderedImage to ensure that notifications occur only when the first writer acquires a tile and the last writer releases it.
| Modifier and Type | Method and Description |
|---|---|
| public void | |
| public WritableRaster | Returns: a writable tile.the X index of the tile. tileX, int the Y index of the tile. tileY)Checks out a tile for writing. |
| public Point[] | Returns: an array containing the locations of tiles that are checked out for writing.Returns an array of Point objects indicating which tiles are checked out for writing. |
| public boolean | Returns: true if any tiles are checked out for
writing; false otherwise.Returns whether any tile is checked out for writing. |
| public boolean | Returns: true if specified tile is checked out
for writing; false otherwise.the X index of the tile. tileX, int the Y index of the tile. tileY)Returns whether a tile is currently checked out for writing. |
| public void | releaseWritableTile(int
the X index of the tile. tileX, int the Y index of the tile. tileY)Relinquishes the right to write to a tile. |
| public void | |
| public void |
| addTileObserver | back to summary |
|---|---|
| public void addTileObserver(TileObserver to) Adds an observer. If the observer is already present, it will receive multiple notifications.
| |
| getWritableTile | back to summary |
|---|---|
| public WritableRaster getWritableTile(int tileX, int tileY) Checks out a tile for writing. The WritableRenderedImage is responsible for notifying all of its TileObservers when a tile goes from having no writers to having one writer.
| |
| getWritableTileIndices | back to summary |
|---|---|
| public Point[] getWritableTileIndices() Returns an array of Point objects indicating which tiles are checked out for writing. Returns null if none are checked out.
| |
| hasTileWriters | back to summary |
|---|---|
| public boolean hasTileWriters() Returns whether any tile is checked out for writing. Semantically equivalent to (getWritableTileIndices() != null).
| |
| isTileWritable | back to summary |
|---|---|
| public boolean isTileWritable(int tileX, int tileY) Returns whether a tile is currently checked out for writing.
| |
| releaseWritableTile | back to summary |
|---|---|
| public void releaseWritableTile(int tileX, int tileY) Relinquishes the right to write to a tile. If the caller continues to write to the tile, the results are undefined. Calls to this 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 TileObservers when a tile goes from having one writer to having no writers.
| |
| removeTileObserver | back to summary |
|---|---|
| public void removeTileObserver(TileObserver to) Removes an observer. If the observer was not registered, nothing happens. If the observer was registered for multiple notifications, it will now be registered for one fewer.
| |
| setData | back to summary |
|---|---|
| public void setData(Raster r) Sets a rect of the image to the contents of the Raster r, which is assumed to be in the same coordinate space as the WritableRenderedImage. The operation is clipped to the bounds of the WritableRenderedImage.
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