src/gallium/auxiliary/util/u_format_srgb.py

   1 #!/usr/bin/env python
   2
   3 '''
   4 /**************************************************************************
   5  *
   6  * Copyright 2010 VMware, Inc.
   7  * All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the
  11  * "Software"), to deal in the Software without restriction, including
  12  * without limitation the rights to use, copy, modify, merge, publish,
  13  * distribute, sub license, and/or sell copies of the Software, and to
  14  * permit persons to whom the Software is furnished to do so, subject to
  15  * the following conditions:
  16  *
  17  * The above copyright notice and this permission notice (including the
  18  * next paragraph) shall be included in all copies or substantial portions
  19  * of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  22  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  24  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  25  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  26  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  27  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28  *
  29  **************************************************************************/
  30
  31 /**
  32  * @file
  33  * SRGB translation.
  34  *
  35  * @author Brian Paul <brianp@vmware.com>
  36  * @author Michal Krol <michal@vmware.com>
  37  * @author Jose Fonseca <jfonseca@vmware.com>
  38  */
  39 '''
  40
  41
  42 import sys
  43 import math
  44
  45
  46 def srgb_to_linear(x):
  47     if x <= 0.04045:
  48         return x / 12.92
  49     else:
  50         return math.pow((x + 0.055) / 1.055, 2.4)
  51
  52
  53 def linear_to_srgb(x):
  54     if x >= 0.0031308:
  55         return 1.055 * math.pow(x, 0.41666) - 0.055
  56     else:
  57         return 12.92 * x
  58
  59 def generate_srgb_tables():
  60     print 'const float'
  61     print 'util_format_srgb_8unorm_to_linear_float_table[256] = {'
  62     for j in range(0, 256, 4):
  63         print '   ',
  64         for i in range(j, j + 4):
  65             print '%.7e,' % (srgb_to_linear(i / 255.0),),
  66         print
  67     print '};'
  68     print
  69     print 'const uint8_t'
  70     print 'util_format_srgb_to_linear_8unorm_table[256] = {'
  71     for j in range(0, 256, 16):
  72         print '   ',
  73         for i in range(j, j + 16):
  74             print '%3u,' % (int(srgb_to_linear(i / 255.0) * 255.0 + 0.5),),
  75         print
  76     print '};'
  77     print
  78     print 'const uint8_t'
  79     print 'util_format_linear_to_srgb_8unorm_table[256] = {'
  80     for j in range(0, 256, 16):
  81         print '   ',
  82         for i in range(j, j + 16):
  83             print '%3u,' % (int(linear_to_srgb(i / 255.0) * 255.0 + 0.5),),
  84         print
  85     print '};'
  86     print
  87
  88
  89 def main():
  90     print '/* This file is autogenerated by u_format_srgb.py. Do not edit directly. */'
  91     print
  92     # This will print the copyright message on the top of this file
  93     print __doc__.strip()
  94     print
  95     print '#include "u_format_srgb.h"'
  96     print
  97     generate_srgb_tables()
  98
  99
 100 if __name__ == '__main__':
 101     main()