Source for gnu.javax.imageio.png.PNGPhys

   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: }