aces_1.0.0/python/aces_ocio/colorspaces/panasonic.py

   1 #!/usr/bin/env python
   2 # -*- coding: utf-8 -*-
   3
   4 """
   5 Implements support for *Panasonic* colorspaces conversions and transfer
   6 functions.
   7 """
   8
   9 import array
  10 import os
  11
  12 import PyOpenColorIO as ocio
  13
  14 import aces_ocio.generate_lut as genlut
  15 from aces_ocio.utilities import ColorSpace
  16
  17 __author__ = 'ACES Developers'
  18 __copyright__ = 'Copyright (C) 2014 - 2015 - ACES Developers'
  19 __license__ = ''
  20 __maintainer__ = 'ACES Developers'
  21 __email__ = 'aces@oscars.org'
  22 __status__ = 'Production'
  23
  24 __all__ = ['create_v_log',
  25            'create_colorspaces']
  26
  27
  28 def create_v_log(gamut,
  29                  transfer_function,
  30                  name,
  31                  lut_directory,
  32                  lut_resolution_1d,
  33                  aliases):
  34     """
  35     Object description.
  36
  37     Panasonic V-Log to ACES.
  38
  39     Parameters
  40     ----------
  41     parameter : type
  42         Parameter description.
  43
  44     Returns
  45     -------
  46     type
  47          Return value description.
  48     """
  49
  50     name = '%s - %s' % (transfer_function, gamut)
  51     if transfer_function == '':
  52         name = 'Linear - %s' % gamut
  53     if gamut == '':
  54         name = 'Curve - %s' % transfer_function
  55
  56     cs = ColorSpace(name)
  57     cs.description = name
  58     cs.aliases = aliases
  59     cs.equality_group = ''
  60     cs.family = 'Input/Panasonic'
  61     cs.is_data = False
  62
  63     # A linear space needs allocation variables
  64     if transfer_function == '':
  65         cs.allocation_type = ocio.Constants.ALLOCATION_LG2
  66         cs.allocation_vars = [-8, 5, 0.00390625]
  67
  68     def v_log_to_linear(x):
  69         cutInv = 0.181
  70         b = 0.00873
  71         c = 0.241514
  72         d = 0.598206
  73
  74         if (x <= cutInv):
  75             return (x - 0.125) / 5.6
  76         else:
  77             return pow(10, (x - d) / c) - b
  78
  79     cs.to_reference_transforms = []
  80
  81     if transfer_function == 'V-Log':
  82         data = array.array('f', '\0' * lut_resolution_1d * 4)
  83         for c in range(lut_resolution_1d):
  84             data[c] = v_log_to_linear(float(c) / (lut_resolution_1d - 1))
  85
  86         lut = '%s_to_linear.spi1d' % transfer_function
  87         genlut.write_SPI_1d(
  88             os.path.join(lut_directory, lut),
  89             0.0,
  90             1.0,
  91             data,
  92             lut_resolution_1d,
  93             1)
  94
  95         cs.to_reference_transforms.append({
  96             'type': 'lutFile',
  97             'path': lut,
  98             'interpolation': 'linear',
  99             'direction': 'forward'})
 100
 101     if gamut == 'V-Gamut':
 102         cs.to_reference_transforms.append({
 103             'type': 'matrix',
 104             'matrix': [0.724382758, 0.166748484, 0.108497411, 0.0,
 105                        0.021354009, 0.985138372, -0.006319092, 0.0,
 106                        -0.009234278, -0.00104295, 1.010272625, 0.0,
 107                        0, 0, 0, 1.0],
 108             'direction': 'forward'})
 109
 110     cs.from_reference_transforms = []
 111     return cs
 112
 113
 114 def create_colorspaces(lut_directory, lut_resolution_1d):
 115     """
 116     Generates the colorspace conversions.
 117
 118     Parameters
 119     ----------
 120     parameter : type
 121         Parameter description.
 122
 123     Returns
 124     -------
 125     type
 126          Return value description.
 127     """
 128
 129     colorspaces = []
 130
 131     # Full conversion
 132     v_log_1 = create_v_log(
 133         'V-Gamut',
 134         'V-Log',
 135         'V-Log',
 136         lut_directory,
 137         lut_resolution_1d,
 138         ['vlog_vgamut'])
 139     colorspaces.append(v_log_1)
 140
 141     # Linearization Only
 142     v_log_2 = create_v_log(
 143         '',
 144         'V-Log',
 145         'V-Log',
 146         lut_directory,
 147         lut_resolution_1d,
 148         ['crv_vlog'])
 149     colorspaces.append(v_log_2)
 150
 151     # Primaries Only
 152     v_log_3 = create_v_log(
 153         'V-Gamut',
 154         '',
 155         'V-Log',
 156         lut_directory,
 157         lut_resolution_1d,
 158         ['lin_vgamut'])
 159     colorspaces.append(v_log_3)
 160
 161     return colorspaces