001 /* FilteredImageSource.java -- Java class for providing image data
002 Copyright (C) 1999 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.awt.image;
040
041 import java.util.Hashtable;
042
043 /**
044 *
045 * @see ImageConsumer
046 * @author C. Brian Jones (cbj@gnu.org)
047 */
048 public class FilteredImageSource implements ImageProducer
049 {
050 ImageProducer ip;
051 ImageFilter filter;
052 Hashtable consumers = new Hashtable();
053
054 /**
055 * The given filter is applied to the given image producer
056 * to create a new image producer.
057 */
058 public FilteredImageSource(ImageProducer ip, ImageFilter filter) {
059 this.ip = ip;
060 this.filter = filter;
061 }
062
063 /**
064 * Used to register an <code>ImageConsumer</code> with this
065 * <code>ImageProducer</code>.
066 */
067 public synchronized void addConsumer(ImageConsumer ic) {
068 if (consumers.containsKey(ic))
069 return;
070
071 ImageFilter f = filter.getFilterInstance(ic);
072 consumers.put(ic, f);
073 ip.addConsumer(f);
074 }
075
076 /**
077 * Used to determine if the given <code>ImageConsumer</code> is
078 * already registered with this <code>ImageProducer</code>.
079 */
080 public synchronized boolean isConsumer(ImageConsumer ic) {
081 ImageFilter f = (ImageFilter)consumers.get(ic);
082 if (f != null)
083 return ip.isConsumer(f);
084 return false;
085 }
086
087 /**
088 * Used to remove an <code>ImageConsumer</code> from the list of
089 * registered consumers for this <code>ImageProducer</code>.
090 */
091 public synchronized void removeConsumer(ImageConsumer ic) {
092 ImageFilter f = (ImageFilter)consumers.remove(ic);
093 if (f != null)
094 ip.removeConsumer(f);
095 }
096
097 /**
098 * Used to register an <code>ImageConsumer</code> with this
099 * <code>ImageProducer</code> and then immediately start
100 * reconstruction of the image data to be delivered to all
101 * registered consumers.
102 */
103 public void startProduction(ImageConsumer ic) {
104 ImageFilter f;
105 if (!(consumers.containsKey(ic))) {
106 f = filter.getFilterInstance(ic);
107 consumers.put(ic, f);
108 ip.addConsumer(f);
109 } else {
110 f = (ImageFilter)consumers.get( ic );
111 }
112 ip.startProduction(f);
113 }
114
115 /**
116 * Used to register an <code>ImageConsumer</code> with this
117 * <code>ImageProducer</code> and then request that this producer
118 * resend the image data in the order top-down, left-right.
119 */
120 public void requestTopDownLeftRightResend(ImageConsumer ic) {
121 ImageFilter f = (ImageFilter)consumers.get(ic);
122 ip.requestTopDownLeftRightResend(f);
123 }
124 }