1 #! /usr/bin/python

     2 # Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

     3 #

     4 # Permission is hereby granted, free of charge, to any person obtaining a

     5 # copy of this software and /or associated documentation files

     6 # (the "Materials "), to deal in the Materials without restriction,

     7 # including without limitation the rights to use, copy, modify, merge,

     8 # publish, distribute, sublicense, and/or sell copies of the Materials,

     9 # and to permit persons to whom the Materials are furnished to do so,

    10 # subject to the following conditions:

    11 #

    12 # The above copyright notice and this permission notice shall be included

    13 # in all copies or substantial portions of the Materials.

    14 #

    15 # THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

    16 # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

    17 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

    18 # IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

    19 # DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

    20 # OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE MATERIALS OR

    21 # THE USE OR OTHER DEALINGS IN THE MATERIALS.

    22 

    23 # Extremely coarse lrgb<->srgb conversion table generation

    24 

    25 from c_utils import *

    26 

    27 GAMMA_BITS = 8

    28 

    29 def linear_to_gamma(f):

    30     if f <= 0.00304:

    31         return 12.92 * f

    32     return 1.0556*pow(f, 1/2.4) - 0.0556

    33 

    34 def gamma_to_linear(f):

    35     if f <= 0.03928:

    36         return f / 12.92

    37     return pow((f+0.0556)/1.0556, 2.4)

    38 

    39 def clamp(i, mn, mx):

    40     if i < mn:

    41         return mn

    42     if i > mx:

    43         return mx

    44     return i

    45 

    46 def icolortof(i):

    47     return i / 255.0

    48 

    49 def fcolortoi(f):

    50     return int(f * ((1<<GAMMA_BITS)-1) + 0.5)

    51 

    52 all_components = range(0,256)

    53 all_floats = map(icolortof, all_components)

    54 

    55 def make_color_list(conv_func):

    56     return map(fcolortoi, map(conv_func, all_floats))

    57 

    58 def make_lut_array(name, data):

    59     make_array("static const", "RIuint8", name, data, hex_formatter)  

    60 

    61 def print_lrgb_to_srgb_table():

    62     make_lut_array("sc_lRGB_to_sRGB", make_color_list(linear_to_gamma))

    63 

    64 def print_srgb_to_lrgb_table():

    65     make_lut_array("sc_sRGB_to_lRGB", make_color_list(gamma_to_linear))

    66 

    67 def print_lookups():

    68     begin_include_guard("_SFGAMMARCP_H_") 

    69     print ""

    70     make_include("riDefs.h")

    71     print ""

    72     begin_namespace("OpenVGRI")

    73     print_srgb_to_lrgb_table()

    74     print ""

    75     print_lrgb_to_srgb_table()

    76     end_namespace()

    77     end_include_guard()

    78 

    79 if __name__ == '__main__':

    80     print_lookups()

    81