001/* ImageFilter.java -- Java class for filtering images 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 * The <code>ImageFilter</code> class is a base class which can be 045 * extended to provide different types of filters for an image. By 046 * default this class does nothing to an image passing through it. 047 * 048 * @author C. Brian Jones (cbj@gnu.org) 049 */ 050public class ImageFilter implements ImageConsumer, Cloneable 051{ 052 /** 053 * The consumer this filter is filtering an image data stream for. 054 * It is initialized in the method <code>getFilterInstance</code>. 055 */ 056 protected ImageConsumer consumer = null; 057 058 /** 059 * The <code>ImageConsumer</code> can use this method to request 060 * the pixels be delivered in top-down, left-right order. 061 * <br> 062 * The filter can respond in three different ways. 063 * <ul> 064 * <li>The default behavior is to forward the request to the 065 * <code>ImageProducer</code> 066 * using the method <code>requestTopDownLeftRightResend</code> 067 * and using the filter as the consumer.</li> 068 * <li>The filter has the pixels and can retransmit them in the 069 * top-down, left-right order.</li> 070 * <li>The filter can do nothing when this method is called.</li> 071 * </ul> 072 */ 073 public void resendTopDownLeftRight(ImageProducer ip) 074 { 075 ip.requestTopDownLeftRightResend(this); 076 } 077 078 /** 079 * By default, returns a shallow copy of the object created by 080 * <code>Object.clone()</code> 081 * 082 * @see java.lang.Object#clone () 083 */ 084 public Object clone() 085 { 086 try 087 { 088 return super.clone(); 089 } 090 catch (CloneNotSupportedException e) 091 { 092 // This should never happen as this class implements the 093 // Cloneable interface. 094 throw new InternalError (); 095 } 096 } 097 098 /** 099 * This is the only method which can set the 100 * <code>ImageConsumer</code> for this filter. By default a clone 101 * of this filter with the appropriate consumer set is returned. 102 * 103 * @see #clone () 104 */ 105 public ImageFilter getFilterInstance(ImageConsumer ic) 106 { 107 ImageFilter f = (ImageFilter)clone(); 108 f.consumer = ic; 109 return f; 110 } 111 112 /** 113 * An <code>ImageProducer</code> indicates the size of the image 114 * being produced using this method. A filter can override this 115 * method to intercept these calls from the producer in order to 116 * change either the width or the height before in turn calling 117 * the consumer's <code>setDimensions</code> method. 118 * 119 * @param width the width of the image 120 * @param height the height of the image 121 */ 122 public void setDimensions(int width, int height) 123 { 124 consumer.setDimensions(width, height); 125 } 126 127 /** 128 * An <code>ImageProducer</code> can set a list of properties 129 * associated with this image by using this method. 130 * 131 * @param props the list of properties associated with this image 132 */ 133 public void setProperties(Hashtable<?,?> props) 134 { 135 Hashtable copy = (Hashtable) props.clone(); 136 Object o = copy.get("filters"); 137 if (o == null) 138 copy.put("filters", toString()); 139 else if (o instanceof String) 140 copy.put("filters", ((String) o) + toString()); 141 142 consumer.setProperties(copy); 143 } 144 145 /** 146 * Override this method to process calls to this method from the 147 * <code>ImageProducer</code>. By default the <code>setColorModel</code> 148 * method of the consumer is called with the specified <code>model</code>. 149 * 150 * @param model the color model to be used most often by setPixels 151 * 152 * @see ColorModel 153 */ 154 public void setColorModel(ColorModel model) 155 { 156 consumer.setColorModel(model); 157 } 158 159 /** 160 * The <code>ImageProducer</code> should call this method with a 161 * bit mask of hints from any of <code>RANDOMPIXELORDER</code>, 162 * <code>TOPDOWNLEFTRIGHT</code>, <code>COMPLETESCANLINES</code>, 163 * <code>SINGLEPASS</code>, <code>SINGLEFRAME</code> from the 164 * <code>ImageConsumer</code> interface. 165 * 166 * @param flags a bit mask of hints 167 * @see ImageConsumer 168 */ 169 public void setHints(int flags) 170 { 171 consumer.setHints(flags); 172 } 173 174 /** 175 * This function delivers a rectangle of pixels where any 176 * pixel(m,n) is stored in the array as a <code>byte</code> at 177 * index (n * scansize + m + offset). 178 * 179 * @param x the x coordinate of the rectangle 180 * @param y the y coordinate of the rectangle 181 * @param w the width of the rectangle 182 * @param h the height of the rectangle 183 * @param model the <code>ColorModel</code> used to translate the pixels 184 * @param pixels the array of pixel values 185 * @param offset the index of the first pixels in the <code>pixels</code> array 186 * @param scansize the width to use in extracting pixels from the <code>pixels</code> array 187 */ 188 public void setPixels(int x, int y, int w, int h, 189 ColorModel model, byte[] pixels, int offset, 190 int scansize) 191 { 192 consumer.setPixels(x, y, w, h, model, pixels, offset, scansize); 193 } 194 195 /** 196 * This function delivers a rectangle of pixels where any 197 * pixel(m,n) is stored in the array as an <code>int</code> at 198 * index (n * scansize + m + offset). 199 * 200 * @param x the x coordinate of the rectangle 201 * @param y the y coordinate of the rectangle 202 * @param w the width of the rectangle 203 * @param h the height of the rectangle 204 * @param model the <code>ColorModel</code> used to translate the pixels 205 * @param pixels the array of pixel values 206 * @param offset the index of the first pixels in the <code>pixels</code> array 207 * @param scansize the width to use in extracting pixels from the <code>pixels</code> array 208 */ 209 public void setPixels(int x, int y, int w, int h, 210 ColorModel model, int[] pixels, int offset, 211 int scansize) 212 { 213 consumer.setPixels(x, y, w, h, model, pixels, offset, scansize); 214 } 215 216 /** 217 * The <code>ImageProducer</code> calls this method to indicate a 218 * single frame or the entire image is complete. The method is 219 * also used to indicate an error in loading or producing the 220 * image. 221 */ 222 public void imageComplete(int status) 223 { 224 consumer.imageComplete(status); 225 } 226}