1 /*
2 * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 /* ****************************************************************
27 ******************************************************************
28 ******************************************************************
29 *** COPYRIGHT (c) Eastman Kodak Company, 1997
30 *** As an unpublished work pursuant to Title 17 of the United
31 *** States Code. All rights reserved.
32 ******************************************************************
33 ******************************************************************
34 ******************************************************************/
35
36 package java.awt.image;
37 import java.awt.Point;
38
39 /**
40 * WritableRenderedImage is a common interface for objects which
41 * contain or can produce image data in the form of Rasters and
42 * which can be modified and/or written over. The image
43 * data may be stored/produced as a single tile or a regular array
44 * of tiles.
45 * <p>
46 * WritableRenderedImage provides notification to other interested
47 * objects when a tile is checked out for writing (via the
48 * getWritableTile method) and when the last writer of a particular
49 * tile relinquishes its access (via a call to releaseWritableTile).
50 * Additionally, it allows any caller to determine whether any tiles
51 * are currently checked out (via hasTileWriters), and to obtain a
52 * list of such tiles (via getWritableTileIndices, in the form of a Vector
53 * of Point objects).
54 * <p>
55 * Objects wishing to be notified of changes in tile writability must
56 * implement the TileObserver interface, and are added by a
57 * call to addTileObserver. Multiple calls to
58 * addTileObserver for the same object will result in multiple
59 * notifications. An existing observer may reduce its notifications
60 * by calling removeTileObserver; if the observer had no
61 * notifications the operation is a no-op.
62 * <p>
63 * It is necessary for a WritableRenderedImage to ensure that
64 * notifications occur only when the first writer acquires a tile and
65 * the last writer releases it.
66 *
67 */
68
69 public interface WritableRenderedImage extends RenderedImage
70 {
71
72 /**
73 * Adds an observer. If the observer is already present,
74 * it will receive multiple notifications.
75 * @param to the specified <code>TileObserver</code>
76 */
77 public void addTileObserver(TileObserver to);
78
79 /**
80 * Removes an observer. If the observer was not registered,
81 * nothing happens. If the observer was registered for multiple
82 * notifications, it will now be registered for one fewer.
83 * @param to the specified <code>TileObserver</code>
84 */
85 public void removeTileObserver(TileObserver to);
86
87 /**
88 * Checks out a tile for writing.
89 *
90 * The WritableRenderedImage is responsible for notifying all
91 * of its TileObservers when a tile goes from having
92 * no writers to having one writer.
93 *
94 * @param tileX the X index of the tile.
95 * @param tileY the Y index of the tile.
96 * @return a writable tile.
97 */
98 public WritableRaster getWritableTile(int tileX, int tileY);
99
100 /**
101 * Relinquishes the right to write to a tile. If the caller
102 * continues to write to the tile, the results are undefined.
103 * Calls to this method should only appear in matching pairs
104 * with calls to getWritableTile; any other use will lead
105 * to undefined results.
106 *
107 * The WritableRenderedImage is responsible for notifying all of
108 * its TileObservers when a tile goes from having one writer
109 * to having no writers.
110 *
111 * @param tileX the X index of the tile.
112 * @param tileY the Y index of the tile.
113 */
114 public void releaseWritableTile(int tileX, int tileY);
115
116 /**
117 * Returns whether a tile is currently checked out for writing.
118 *
119 * @param tileX the X index of the tile.
120 * @param tileY the Y index of the tile.
121 * @return <code>true</code> if specified tile is checked out
122 * for writing; <code>false</code> otherwise.
123 */
124 public boolean isTileWritable(int tileX, int tileY);
125
126 /**
127 * Returns an array of Point objects indicating which tiles
128 * are checked out for writing. Returns null if none are
129 * checked out.
130 * @return an array containing the locations of tiles that are
131 * checked out for writing.
132 */
133 public Point[] getWritableTileIndices();
134
135 /**
136 * Returns whether any tile is checked out for writing.
137 * Semantically equivalent to (getWritableTileIndices() != null).
138 * @return <code>true</code> if any tiles are checked out for
139 * writing; <code>false</code> otherwise.
140 */
141 public boolean hasTileWriters();
142
143 /**
144 * Sets a rect of the image to the contents of the Raster r, which is
145 * assumed to be in the same coordinate space as the WritableRenderedImage.
146 * The operation is clipped to the bounds of the WritableRenderedImage.
147 * @param r the specified <code>Raster</code>
148 */
149 public void setData(Raster r);
150
151 }