001/* FilteredImageSource.java -- Java class for providing image data 002 Copyright (C) 1999 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package java.awt.image; 040 041import java.util.Hashtable; 042 043/** 044 * 045 * @see ImageConsumer 046 * @author C. Brian Jones (cbj@gnu.org) 047 */ 048public 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} 125