Source for java.awt.image.Kernel

   1: /* Kernel.java -- Java class for an image processing kernel
   2:    Copyright (C) 2004, 2005, 2006,  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: /**
  42:  * Kernel represents an image processing kernel.  It gets used to hold
  43:  * convolution filters among other purposes.  It stores an array of float
  44:  * values representing a 2-dimensional array in row-major order.
  45:  *
  46:  * @author Jerry Quinn (jlquinn@optonline.net)
  47:  */
  48: public class Kernel implements Cloneable
  49: {
  50:   /** The kernel width. */
  51:   private final int width;
  52:   
  53:   /** The kernel height. */
  54:   private final int height;
  55:   
  56:   /** Internal storage for the kernel's values. */
  57:   private final float[] data;
  58: 
  59:   /**
  60:    * Creates a new <code>Kernel</code> instance with the specified dimensions
  61:    * and values.  The first <code>width * height</code> values in the specified
  62:    * <code>data</code> array are copied to internal storage.
  63:    *
  64:    * @param width  the kernel width.
  65:    * @param height  the kernel height.
  66:    * @param data  the source data array (<code>null</code> not permitted).
  67:    * 
  68:    * @throws IllegalArgumentException if <code>data.length</code> is less than
  69:    *     <code>width * height</code>.
  70:    * @throws IllegalArgumentException if <code>width</code> or 
  71:    *      <code>height</code> is less than zero.
  72:    * @throws NullPointerException if <code>data</code> is <code>null</code>.
  73:    */
  74:   public Kernel(int width, int height, float[] data)
  75:     throws IllegalArgumentException
  76:   {
  77:     this.width = width;
  78:     this.height = height;
  79:     if (data.length < width * height || width < 0 || height < 0)
  80:       throw new IllegalArgumentException();
  81:     this.data = new float[width * height];
  82:     System.arraycopy(data, 0, this.data, 0, width * height);
  83:   }
  84: 
  85:   /**
  86:    * Returns the x-origin for the kernel, which is calculated as 
  87:    * <code>(width - 1) / 2</code>.
  88:    * 
  89:    * @return The x-origin for the kernel.
  90:    */
  91:   public final int getXOrigin()
  92:   {
  93:     return (width - 1) / 2;
  94:   }
  95: 
  96:   /**
  97:    * Returns the y-origin for the kernel, which is calculated as
  98:    * <code>(height - 1) / 2</code>.
  99:    * 
 100:    * @return The y-origin for the kernel.
 101:    */
 102:   public final int getYOrigin()
 103:   {
 104:     return (height - 1) / 2;
 105:   }
 106: 
 107:   /**
 108:    * Returns the kernel width (as supplied to the constructor).
 109:    * 
 110:    * @return The kernel width.
 111:    */
 112:   public final int getWidth()
 113:   {
 114:     return width;
 115:   }
 116: 
 117:   /**
 118:    * Returns the kernel height (as supplied to the constructor).
 119:    * 
 120:    * @return The kernel height.
 121:    */
 122:   public final int getHeight()
 123:   {
 124:     return height;
 125:   }
 126: 
 127:   /**
 128:    * Returns an array containing a copy of the kernel data.  If the 
 129:    * <code>data</code> argument is non-<code>null</code>, the kernel values
 130:    * are copied into it and then <code>data</code> is returned as the result.
 131:    * If the <code>data</code> argument is <code>null</code>, this method 
 132:    * allocates a new array then populates and returns it.
 133:    *
 134:    * @param data  an array to copy the return values into (if 
 135:    *     <code>null</code>, a new array is allocated).
 136:    *     
 137:    * @return The array with copied values.
 138:    * 
 139:    * @throws IllegalArgumentException if <code>data.length</code> is less than 
 140:    *     the kernel's <code>width * height</code>.
 141:    */
 142:   public final float[] getKernelData(float[] data)
 143:     throws IllegalArgumentException
 144:   {
 145:     if (data == null)
 146:       return (float[]) this.data.clone();
 147: 
 148:     if (data.length < this.data.length)
 149:       throw new IllegalArgumentException();
 150: 
 151:     System.arraycopy(this.data, 0, data, 0, this.data.length);
 152:     return data;
 153:   }
 154: 
 155:   /**
 156:    * Returns a clone of this kernel.
 157:    * 
 158:    * @return a clone of this Kernel.
 159:    */
 160:   public Object clone()
 161:   {
 162:     try
 163:       {
 164:         return super.clone();
 165:       }
 166:     catch (CloneNotSupportedException e)
 167:       {
 168:         throw (Error) new InternalError().initCause(e); // Impossible
 169:       }
 170:   }
 171: }