libjava/classpath/gnu/javax/imageio/png/PNGPhys.java

   1 /* PNGPhys.java --
   2    Copyright (C) 2006 Free Software Foundation
   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 package gnu.javax.imageio.png;
  39
  40 /**
  41  * A PNG "pHYS" chunk - pixel physical dimensions
  42  */
  43 public class PNGPhys extends PNGChunk
  44 {
  45   long x, y;
  46   double ratio;
  47   boolean usesRatio;
  48
  49   protected PNGPhys( int type, byte[] data, int crc ) throws PNGException
  50   {
  51     super( type, data, crc );
  52     if( data.length < 9 )
  53       throw new PNGException("Unexpected size of pHYS chunk.");
  54     x = ((data[0] & 0xFF) << 24) | ( (data[1] & 0xFF) << 16 ) |
  55       ((data[2] & 0xFF) << 8) | (data[3] & 0xFF);
  56     y = ((data[4] & 0xFF) << 24) | ( (data[5] & 0xFF) << 16 ) |
  57       ((data[6] & 0xFF) << 8) | (data[7] & 0xFF);
  58     if(data[8] == 0)
  59       {
  60         ratio = ((double)x)/((double)y);
  61         usesRatio = true;
  62       }
  63   }
  64
  65   public PNGPhys( double ratio )
  66   {
  67     super( TYPE_PHYS );
  68
  69     this.ratio = ratio;
  70     usesRatio = true;
  71
  72     if( ratio < 1.0 )
  73       {
  74         y = 0xFFFFFFFF;
  75         x = (long)(0xFFFFFFFFL * ratio);
  76       }
  77     else
  78       {
  79         x = 0xFFFFFFFF;
  80         y = (long)(0xFFFFFFFFL * ratio);
  81       }
  82     makeData();
  83   }
  84
  85   public PNGPhys( int x, int y )
  86   {
  87     super( TYPE_PHYS );
  88     usesRatio = false;
  89     this.x = x;
  90     this.y = y;
  91     makeData();
  92   }
  93
  94   private void makeData()
  95   {
  96     data = new byte[ 9 ];
  97     byte[] a = getInt( (int)x );
  98     byte[] b = getInt( (int)y );
  99     data[0] = a[0]; data[1] = a[1]; data[2] = a[2]; data[3] = a[3];
 100     data[4] = b[0]; data[5] = b[1]; data[6] = b[2]; data[7] = b[3];
 101     data[7] = (usesRatio) ? 0 : (byte)0xFF;
 102   }
 103
 104   public String toString()
 105   {
 106     String s = "PNG Physical pixel size chunk.";
 107     if( usesRatio )
 108       return s + " Aspect ratio (x/y): " + ratio;
 109     else
 110       return s + " " + x + " by " + y + " pixels per meter. (x, y).";
 111   }
 112 }