Source for java.awt.image.FilteredImageSource

   1: /* FilteredImageSource.java -- Java class for providing image data 
   2:    Copyright (C) 1999 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.awt.image;
  40: 
  41: import java.util.Hashtable;
  42: 
  43: /**
  44:  *
  45:  * @see ImageConsumer
  46:  * @author C. Brian Jones (cbj@gnu.org) 
  47:  */
  48: public class FilteredImageSource implements ImageProducer
  49: {
  50:     ImageProducer ip;
  51:     ImageFilter filter;
  52:     Hashtable consumers = new Hashtable();
  53: 
  54:     /**
  55:      * The given filter is applied to the given image producer
  56:      * to create a new image producer.  
  57:      */
  58:     public FilteredImageSource(ImageProducer ip, ImageFilter filter) {
  59:     this.ip = ip;
  60:     this.filter = filter;
  61:     }
  62: 
  63:     /**
  64:      * Used to register an <code>ImageConsumer</code> with this
  65:      * <code>ImageProducer</code>.  
  66:      */
  67:     public synchronized void addConsumer(ImageConsumer ic) {
  68:     if (consumers.containsKey(ic))
  69:         return;
  70: 
  71:     ImageFilter f = filter.getFilterInstance(ic);
  72:     consumers.put(ic, f);
  73:     ip.addConsumer(f);
  74:     }
  75: 
  76:     /**
  77:      * Used to determine if the given <code>ImageConsumer</code> is
  78:      * already registered with this <code>ImageProducer</code>.  
  79:      */
  80:     public synchronized boolean isConsumer(ImageConsumer ic) {
  81:     ImageFilter f = (ImageFilter)consumers.get(ic);
  82:     if (f != null)
  83:         return ip.isConsumer(f);
  84:     return false;
  85:     }
  86: 
  87:     /**
  88:      * Used to remove an <code>ImageConsumer</code> from the list of
  89:      * registered consumers for this <code>ImageProducer</code>.  
  90:      */
  91:     public synchronized void removeConsumer(ImageConsumer ic) {
  92:     ImageFilter f = (ImageFilter)consumers.remove(ic);
  93:     if (f != null)
  94:         ip.removeConsumer(f);
  95:     }
  96: 
  97:     /**
  98:      * Used to register an <code>ImageConsumer</code> with this
  99:      * <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: }