libjava/java/awt/image/ImageFilter.java

   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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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 }
 221