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	/*
	* Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/* ****************************************************************
	******************************************************************
	******************************************************************
	*** COPYRIGHT (c) Eastman Kodak Company, 1997
	*** As an unpublished work pursuant to Title 17 of the United
	*** States Code. All rights reserved.
	******************************************************************
	******************************************************************
	******************************************************************/

	package java.awt.image;
	import java.awt.Point;

	/**
	* WriteableRenderedImage is a common interface for objects which
	* contain or can produce image data in the form of Rasters and
	* which can be modified and/or written over. The image
	* data may be stored/produced as a single tile or a regular array
	* of tiles.
	* <p>
	* 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).
	* <p>
	* 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.
	* <p>
	* 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.
	*
	*/

	public interface WritableRenderedImage extends RenderedImage
	{

	/**
	* Adds an observer. If the observer is already present,
	* it will receive multiple notifications.
	* @param to the specified <code>TileObserver</code>
	*/
	public void addTileObserver(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.
	* @param to the specified <code>TileObserver</code>
	*/
	public void removeTileObserver(TileObserver to);

	/**
	* 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.
	*
	* @param tileX the X index of the tile.
	* @param tileY the Y index of the tile.
	* @return a writable tile.
	*/
	public WritableRaster getWritableTile(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.
	*
	* @param tileX the X index of the tile.
	* @param tileY the Y index of the tile.
	*/
	public void releaseWritableTile(int tileX, int tileY);

	/**
	* Returns whether a tile is currently checked out for writing.
	*
	* @param tileX the X index of the tile.
	* @param tileY the Y index of the tile.
	* @return <code>true</code> if specified tile is checked out
	* for writing; <code>false</code> otherwise.
	*/
	public boolean isTileWritable(int tileX, int tileY);

	/**
	* Returns an array of Point objects indicating which tiles
	* are checked out for writing. Returns null if none are
	* checked out.
	* @return an array containing the locations of tiles that are
	* checked out for writing.
	*/
	public Point[] getWritableTileIndices();

	/**
	* Returns whether any tile is checked out for writing.
	* Semantically equivalent to (getWritableTileIndices() != null).
	* @return <code>true</code> if any tiles are checked out for
	* writing; <code>false</code> otherwise.
	*/
	public boolean hasTileWriters();

	/**
	* 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.
	* @param r the specified <code>Raster</code>
	*/
	public void setData(Raster r);

	}

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