Source for java.awt.image.ImageFilter

   1: /* ImageFilter.java -- Java class for filtering images
   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:  * The <code>ImageFilter</code> class is a base class which can be
  45:  * extended to provide different types of filters for an image.  By
  46:  * default this class does nothing to an image passing through it.
  47:  *
  48:  * @author C. Brian Jones (cbj@gnu.org) 
  49:  */
  50: public class ImageFilter implements ImageConsumer, Cloneable
  51: {
  52:     /**
  53:      * The consumer this filter is filtering an image data stream for.
  54:      * It is initialized in the method <code>getFilterInstance</code>.  
  55:      */
  56:     protected ImageConsumer consumer = null;
  57: 
  58:     /**
  59:      * The <code>ImageConsumer</code> can use this method to request
  60:      * the pixels be delivered in top-down, left-right order.  
  61:      * <br> 
  62:      * The filter can respond in three different ways.  
  63:      * <ul>
  64:      *   <li>The default behavior is to forward the request to the 
  65:      *       <code>ImageProducer</code> 
  66:      *       using the method <code>requestTopDownLeftRightResend</code>
  67:      *       and using the filter as the consumer.</li>
  68:      *   <li>The filter has the pixels and can retransmit them in the
  69:      *       top-down, left-right order.</li>
  70:      *   <li>The filter can do nothing when this method is called.</li>
  71:      * </ul>
  72:      */
  73:     public void resendTopDownLeftRight(ImageProducer ip)
  74:     {
  75:     ip.requestTopDownLeftRightResend(this);
  76:     }
  77: 
  78:     /**
  79:      * By default, returns a shallow copy of the object created by
  80:      * <code>Object.clone()</code> 
  81:      *
  82:      * @see java.lang.Object#clone ()
  83:      */
  84:     public Object clone()
  85:     {
  86:       try
  87:         {
  88:           return super.clone();
  89:         }
  90:       catch (CloneNotSupportedException e)
  91:         {
  92:           // This should never happen as this class implements the
  93:           // Cloneable interface.
  94:           throw new InternalError ();
  95:         }
  96:     }
  97: 
  98:     /**
  99:      * 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:     if ( ic == null )
 108:         throw new IllegalArgumentException("null argument for ImageFilter.getFilterInstance(ImageConsumer)");
 109: 
 110:     consumer = ic;
 111:     ImageFilter f = (ImageFilter)clone();
 112:     consumer = null;
 113:     return f;
 114:     }
 115: 
 116:     /**
 117:      * An <code>ImageProducer</code> indicates the size of the image
 118:      * being produced using this method.  A filter can override this 
 119:      * method to intercept these calls from the producer in order to
 120:      * change either the width or the height before in turn calling
 121:      * the consumer's <code>setDimensions</code> method.
 122:      * 
 123:      * @param width the width of the image
 124:      * @param height the height of the image 
 125:      */
 126:     public void setDimensions(int width, int height)
 127:     {
 128:     consumer.setDimensions(width, height);
 129:     }
 130: 
 131:     /**
 132:      * An <code>ImageProducer</code> can set a list of properties
 133:      * associated with this image by using this method.
 134:      *
 135:      * @param props the list of properties associated with this image 
 136:      */
 137:     public void setProperties(Hashtable props)
 138:     {
 139:     props.put("filters", "ImageFilter");
 140:     consumer.setProperties(props);
 141:     }
 142: 
 143:     /**
 144:      * Override this method to process calls to this method from the
 145:      * <code>ImageProducer</code>.  By default the <code>setColorModel</code>
 146:      * method of the consumer is called with the specified <code>model</code>.
 147:      *
 148:      * @param model the color model to be used most often by setPixels
 149:      * @see ColorModel */
 150:     public void setColorModel(ColorModel model)
 151:     {
 152:     consumer.setColorModel(model);
 153:     }
 154: 
 155:     /**
 156:      * The <code>ImageProducer</code> should call this method with a
 157:      * bit mask of hints from any of <code>RANDOMPIXELORDER</code>,
 158:      * <code>TOPDOWNLEFTRIGHT</code>, <code>COMPLETESCANLINES</code>,
 159:      * <code>SINGLEPASS</code>, <code>SINGLEFRAME</code> from the 
 160:      * <code>ImageConsumer</code> interface.
 161:      * 
 162:      * @param flags a bit mask of hints
 163:      * @see ImageConsumer
 164:      */
 165:     public void setHints(int flags)
 166:     {
 167:     consumer.setHints(flags);
 168:     }
 169: 
 170:     /**
 171:      * This function delivers a rectangle of pixels where any
 172:      * pixel(m,n) is stored in the array as a <code>byte</code> at
 173:      * index (n * scansize + m + offset).  
 174:      *
 175:      * @param x the x coordinate of the rectangle
 176:      * @param y the y coordinate of the rectangle
 177:      * @param w the width of the rectangle
 178:      * @param h the height of the rectangle
 179:      * @param model the <code>ColorModel</code> used to translate the pixels
 180:      * @param pixels the array of pixel values
 181:      * @param offset the index of the first pixels in the <code>pixels</code> array
 182:      * @param scansize the width to use in extracting pixels from the <code>pixels</code> array
 183:      */
 184:     public void setPixels(int x, int y, int w, int h, 
 185:        ColorModel model, byte[] pixels, int offset, int scansize)
 186:     {
 187:     consumer.setPixels(x, y, w, h, model, pixels, offset, scansize);
 188:     }
 189: 
 190:     /**
 191:      * This function delivers a rectangle of pixels where any
 192:      * pixel(m,n) is stored in the array as an <code>int</code> at
 193:      * index (n * scansize + m + offset).  
 194:      *
 195:      * @param x the x coordinate of the rectangle
 196:      * @param y the y coordinate of the rectangle
 197:      * @param w the width of the rectangle
 198:      * @param h the height of the rectangle
 199:      * @param model the <code>ColorModel</code> used to translate the pixels
 200:      * @param pixels the array of pixel values
 201:      * @param offset the index of the first pixels in the <code>pixels</code> array
 202:      * @param scansize the width to use in extracting pixels from the <code>pixels</code> array
 203:      */
 204:     public void setPixels(int x, int y, int w, int h, 
 205:            ColorModel model, int[] pixels, int offset, int scansize)
 206:     {
 207:     consumer.setPixels(x, y, w, h, model, pixels, offset, scansize);
 208:     }
 209: 
 210:     /**
 211:      * The <code>ImageProducer</code> calls this method to indicate a
 212:      * single frame or the entire image is complete.  The method is
 213:      * also used to indicate an error in loading or producing the
 214:      * image.  
 215:      */
 216:     public void imageComplete(int status)
 217:     {
 218:     consumer.imageComplete(status);
 219:     }
 220: }