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 }