Java example source code file (WritableRenderedImage.java)

This example Java source code file (WritableRenderedImage.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, point, renderedimage, writableraster, writablerenderedimage

The WritableRenderedImage.java Java example source code

/*
 * 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 *** As  an unpublished  work pursuant to Title 17 of the United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
   */
  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
   */
  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 if specified tile is checked out
   *         for writing; <code>false 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 if any tiles are checked out for
   *         writing; <code>false 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
   */
  public void setData(Raster r);

}