001    /* RGBImageFilter.java -- Java class for filtering Pixels by RGB values
002       Copyright (C) 1999, 2005  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    /**
042     * A filter designed to filter images in the default RGBColorModel regardless of 
043     * the ImageProducer's ColorModel.
044     *
045     * @author Mark Benvenuto (mcb54@columbia.edu)
046     */
047    public abstract class RGBImageFilter extends ImageFilter
048    {
049      protected ColorModel origmodel;
050    
051      protected ColorModel newmodel;
052        
053      /**
054       * Specifies whether to apply the filter to the index entries of the
055       * IndexColorModel. Subclasses should set this to true if the filter
056       * does not depend on the pixel's coordinate.
057       */
058      protected boolean canFilterIndexColorModel = false;
059    
060      /**
061       * Construct new RGBImageFilter.
062       */
063      public RGBImageFilter() 
064      {
065      }
066    
067      /**
068       * Sets the ColorModel used to filter with. If the specified ColorModel is
069       * IndexColorModel and canFilterIndexColorModel is true, we subsitute the
070       * ColorModel for a filtered one here and in setPixels whenever the original
071       * one appears. Otherwise overrides the default ColorModel of ImageProducer
072       * and specifies the default RGBColorModel
073       *
074       * @param model the color model to be used most often by setPixels
075       *
076       * @see ColorModel
077       */
078      public void setColorModel(ColorModel model) 
079      {
080        if ((model instanceof IndexColorModel) && canFilterIndexColorModel)
081          {
082            ColorModel newCM = filterIndexColorModel((IndexColorModel) model);
083            substituteColorModel(model, newCM);
084            consumer.setColorModel(newmodel);
085          }
086        else
087          {
088            consumer.setColorModel(ColorModel.getRGBdefault());
089          }
090      }
091    
092      /**
093       * Registers a new ColorModel to subsitute for the old ColorModel when 
094       * setPixels encounters the a pixel with the old ColorModel. The pixel 
095       * remains unchanged except for a new ColorModel.
096       * 
097       * @param oldcm the old ColorModel
098       * @param newcm the new ColorModel
099       */
100      public void substituteColorModel(ColorModel oldcm, ColorModel newcm)
101      {
102        origmodel = oldcm;
103        newmodel = newcm;
104      }
105    
106      /**
107       * Filters an IndexColorModel through the filterRGB function. Uses
108       * coordinates of -1 to indicate its filtering an index and not a pixel.
109       *
110       * @param icm an IndexColorModel to filter
111       */
112      public IndexColorModel filterIndexColorModel(IndexColorModel icm) 
113      {
114        int len = icm.getMapSize();
115        byte[] reds = new byte[len];
116        byte[] greens = new byte[len];
117        byte[] blues = new byte[len];
118        byte[] alphas = new byte[len];
119    
120        icm.getAlphas( alphas );
121        icm.getReds( reds );
122        icm.getGreens( greens );
123        icm.getBlues( blues );
124    
125        int transparent = icm.getTransparentPixel();
126        boolean needAlpha = false;
127        for( int i = 0; i < len; i++ )
128          {
129            int rgb = filterRGB(-1, -1, icm.getRGB(i));
130            alphas[i] = (byte) (rgb >> 24);
131            if (alphas[i] != ((byte) 0xff) && i != transparent)
132              needAlpha = true;
133            reds[i] = (byte) (rgb >> 16);
134            greens[i] = (byte) (rgb >> 8);
135            blues[i] = (byte) (rgb);
136          }
137        IndexColorModel newIcm;
138        if (needAlpha)
139          newIcm = new IndexColorModel(icm.getPixelSize(), len, reds, greens,
140                                       blues, alphas);
141        else
142          newIcm = new IndexColorModel(icm.getPixelSize(), len, reds, greens,
143                                       blues, transparent);
144        return newIcm;
145      }
146    
147      /**
148       * This functions filters a set of RGB pixels through filterRGB.
149       *
150       * @param x the x coordinate of the rectangle
151       * @param y the y coordinate of the rectangle
152       * @param w the width of the rectangle
153       * @param h the height of the rectangle
154       * @param pixels the array of pixel values
155       * @param offset the index of the first pixels in the
156       *        <code>pixels</code> array
157       * @param scansize the width to use in extracting pixels from the
158       *        <code>pixels</code> array
159       */
160      public void filterRGBPixels(int x, int y, int w, int h, int[] pixels,
161                                  int offset, int scansize)
162      {
163        int index = offset;
164        for (int yp = 0; yp < h; yp++)
165          {
166            for (int xp = 0; xp < w; xp++)
167              {
168                pixels[index] = filterRGB(xp + x, yp + y, pixels[index]);
169                index++;
170              }
171            index += scansize - w;
172          }
173        consumer.setPixels(x, y, w, h, ColorModel.getRGBdefault(), pixels, offset,
174                           scansize);
175      }
176    
177      /**
178       * If the ColorModel is the same ColorModel which as already converted 
179       * then it converts it the converted ColorModel. Otherwise it passes the 
180       * array of pixels through filterRGBpixels.
181       *
182       * @param x the x coordinate of the rectangle
183       * @param y the y coordinate of the rectangle
184       * @param w the width of the rectangle
185       * @param h the height of the rectangle
186       * @param model the <code>ColorModel</code> used to translate the pixels
187       * @param pixels the array of pixel values
188       * @param offset the index of the first pixels in the <code>pixels</code>
189       *        array
190       * @param scansize the width to use in extracting pixels from the
191       *        <code>pixels</code> array
192       */
193      public void setPixels(int x, int y, int w, int h, ColorModel model,
194                            byte[] pixels, int offset, int scansize)
195      {
196        if (model == origmodel)
197          {
198            consumer.setPixels(x, y, w, h, newmodel, pixels, offset, scansize);
199          }
200        else
201          {
202            int[] filtered = new int[w];
203            int index = offset;
204            for (int yp = 0; yp < h; yp++)
205              {
206                for (int xp = 0; xp < w; xp++)
207                  {
208                    filtered[xp] = model.getRGB((pixels[index] & 0xff));
209                    index++;
210                  }
211                index += scansize - w;
212                filterRGBPixels(x, y + yp, w, 1, filtered, 0, w);
213              }
214          }
215      }
216    
217      /**
218       * This function delivers a rectangle of pixels where any
219       * pixel(m,n) is stored in the array as an <code>int</code> at
220       * index (n * scansize + m + offset).  
221       *
222       * @param x the x coordinate of the rectangle
223       * @param y the y coordinate of the rectangle
224       * @param w the width of the rectangle
225       * @param h the height of the rectangle
226       * @param model the <code>ColorModel</code> used to translate the pixels
227       * @param pixels the array of pixel values
228       * @param offset the index of the first pixels in the <code>pixels</code>
229       *        array
230       * @param scansize the width to use in extracting pixels from the
231       *        <code>pixels</code> array
232       */
233      public void setPixels(int x, int y, int w, int h, ColorModel model,
234                            int[] pixels, int offset, int scansize)
235      {
236        if (model == origmodel)
237          {
238            consumer.setPixels(x, y, w, h, newmodel, pixels, offset, scansize);
239          }
240        else
241          {
242            int[] filtered = new int[w];
243            int index = offset;
244            for (int yp = 0; yp < h; yp++)
245              {
246                for (int xp = 0; xp < w; xp++)
247                  {
248                    filtered[xp] = model.getRGB((pixels[index] & 0xff));
249                    index++;
250                  }
251                index += scansize - w;
252                filterRGBPixels(x, y + yp, w, 1, filtered, 0, w);
253              }
254          }
255      }
256    
257      /**
258       * Filters a single pixel from the default ColorModel.
259       *
260       * @param x x-coordinate
261       * @param y y-coordinate
262       * @param rgb color
263       */
264      public abstract int filterRGB(int x, int y, int rgb);
265    }