001 /* ImageFilter.java -- Java class for filtering images
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 * 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 */
050 public 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 }