001/* RGBImageFilter.java -- Java class for filtering Pixels by RGB values
002   Copyright (C) 1999, 2005  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
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 */
047public 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]));
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}