tools/skpdiff/generate_pmetric_tables.py - Issue 1502173003: When was SkPDiff last used?

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Issue 1502173003: When was SkPDiff last used? (Closed) Base URL: https://skia.googlesource.com/skia.git@master

Patch Set: Created 5 years ago

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1 #!/usr/bin/python

2 # -- coding: utf-8 --

3

4 from __future__ import print_function

5 from math import *

6

7

8 COPYRIGHT = '''/*

9 * Copyright 2013 Google Inc.

10 *

11 * Use of this source code is governed by a BSD-style license that can be

12 * found in the LICENSE file.

13 */'''

14

15

16 HELP = '// To regenerate SkPMetricUtil_generated.h, simply run ./generate_pmetri c_tables.py'

17

18

19 # From Barten SPIE 1989

20 def contrast_sensitivity(cycles_per_degree, luminance):

21 a = 440.0 * pow(1.0 + 0.7 / luminance, -0.2)

22 b = 0.3 * pow(1 + 100.0 / luminance, 0.15)

23 return a * cycles_per_degree * exp(-b * cycles_per_degree) * sqrt(1.0 + 0.06 * exp(b * cycles_per_degree))

24

25

26 # From Ward Larson Siggraph 1997

27 def threshold_vs_intensity(adaptation_luminance):

28 log_lum = float('-inf') # Works in Python 2.6+

29 try:

30 log_lum = log10(adaptation_luminance)

31 except ValueError:

32 pass

33

34 x = 0.0

35

36 if log_lum < -3.94:

37 x = -2.86

38

39 elif log_lum < -1.44:

40 x = pow(0.405 * log_lum + 1.6, 2.18) - 2.86

41

42 elif log_lum < -0.0184:

43 x = log_lum - 0.395

44

45 elif log_lum < 1.9:

46 x = pow(0.249 * log_lum + 0.65, 2.7) - 0.72

47

48 else:

49 x = log_lum - 1.255

50

51 return pow(10.0, x)

52

53

54 # From Daly 1993

55 def visual_mask(contrast):

56 x = pow(392.498 * contrast, 0.7)

57 x = pow(0.0153 * x, 4.0)

58 return pow(1.0 + x, 0.25)

59

60

61 # float gCubeRootTable[]

62 CUBE_ROOT_ACCESS_FUNCTION = '''

63 static float get_cube_root(float value) {

64 SkASSERT(value >= 0.0f);

65 SkASSERT(value * 1023.0f < 1024.0f);

66 return gCubeRootTable[(int)(value * 1023.0f)];

67 }

68 '''

69 def generate_cube_root_table(stream):

70 print('static float gCubeRootTable[] = {', end='', file=stream)

71 for i in range(1024):

72 if i % 6 == 0:

73 print('\n ', end='', file=stream)

74 print("%.10f" % pow(i / 1024.0, 1.0 / 3.0), end='f,', file=stream)

75 print('\n};', end='', file=stream)

76 print(CUBE_ROOT_ACCESS_FUNCTION, file=stream)

77

78

79 # float gGammaTable[]

80 GAMMA_ACCESS_FUNCTION = '''

81 static float get_gamma(unsigned char value) {

82 return gGammaTable[value];

83 }

84 '''

85 def generate_gamma_table(stream):

86 print('static float gGammaTable[] = {', end='', file=stream)

87 for i in range(256):

88 if i % 6 == 0:

89 print('\n ', end='', file=stream)

90 print("%.10f" % pow(i / 255.0, 2.2), end='f,', file=stream)

91 print('\n};', end='', file=stream)

92 print(GAMMA_ACCESS_FUNCTION, file=stream)

93

94

95 # float gTVITable[]

96 TVI_ACCESS_FUNCTION = '''

97 static float get_threshold_vs_intensity(float value) {

98 SkASSERT(value >= 0.0f);

99 SkASSERT(value < 100.0f);

100 return gTVITable[(int)(value * 100.0f)];

101 }

102 '''

103 def generate_tvi_table(stream):

104 print('static float gTVITable[] = {', end='', file=stream)

105 for i in range(10000):

106 if i % 6 == 0:

107 print('\n ', end='', file=stream)

108 print("%.10f" % threshold_vs_intensity(i / 100.0), end='f,', file=stream )

109 print('\n};', end='', file=stream)

110 print(TVI_ACCESS_FUNCTION, file=stream)

111

112

113 # float gVisualMaskTable[]

114 VISUAL_MASK_DOMAIN = 4000

115 VISUAL_MASK_ACCESS_FUNCTION = '''

116 static float get_visual_mask(float value) {{

117 SkASSERT(value >= 0.0f);

118 SkASSERT(value < {}.0f);

119 return gVisualMaskTable[(int)value];

120 }}'''

121 def generate_visual_mask_table(stream):

122 print('static float gVisualMaskTable[] = {', end='', file=stream)

123 for i in range(VISUAL_MASK_DOMAIN):

124 if i % 6 == 0:

125 print('\n ', end='', file=stream)

126 print("%.10f" % visual_mask(i), end='f,', file=stream)

127 print('\n};', end='', file=stream)

128 print(VISUAL_MASK_ACCESS_FUNCTION.format(VISUAL_MASK_DOMAIN), file=stream)

129

130

131 def generate_lookup_tables(stream):

132 print(COPYRIGHT, file=stream)

133 print(HELP, file=stream)

134 print('namespace SkPMetricUtil {', file=stream)

135 generate_cube_root_table(stream)

136 generate_gamma_table(stream)

137 generate_tvi_table(stream)

138 generate_visual_mask_table(stream)

139 print('}', file=stream)

140

141

142 def main():

143 pmetric_util_out = open('SkPMetricUtil_generated.h', 'wb')

144 generate_lookup_tables(pmetric_util_out)

145 pmetric_util_out.close()

146

147

148 if __name__ == '__main__':

149 main()

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