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/* * @(#)WritableRenderedImage.java 1.19 05/11/17 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ /* **************************************************************** ****************************************************************** ****************************************************************** *** COPYRIGHT (c) Eastman Kodak Company, 1997 *** As an unpublished work pursuant to Title 17 of the United *** States Code.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); }