/*
* Copyright (c) 1997, 2000, 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*** As an unpublished work pursuant to Title 17 of the United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);
}