5b3e2b9622
R=djsollen@google.com Review URL: https://codereview.chromium.org/19608005 git-svn-id: http://skia.googlecode.com/svn/trunk@10249 2bbb7eff-a529-9590-31e7-b0007b416f81
150 lines
4.1 KiB
Python
Executable File
150 lines
4.1 KiB
Python
Executable File
#!/usr/bin/python
|
|
# -*- coding: utf-8 -*-
|
|
|
|
from __future__ import print_function
|
|
from math import *
|
|
|
|
|
|
COPYRIGHT = '''/*
|
|
* Copyright 2013 Google Inc.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*/'''
|
|
|
|
|
|
HELP = '// To regenerate SkPMetricUtil_generated.h, simply run ./generate_pmetric_tables.py'
|
|
|
|
|
|
# From Barten SPIE 1989
|
|
def contrast_sensitivity(cycles_per_degree, luminance):
|
|
a = 440.0 * pow(1.0 + 0.7 / luminance, -0.2)
|
|
b = 0.3 * pow(1 + 100.0 / luminance, 0.15)
|
|
return a * cycles_per_degree * exp(-b * cycles_per_degree) * sqrt(1.0 + 0.06 * exp(b * cycles_per_degree))
|
|
|
|
|
|
# From Ward Larson Siggraph 1997
|
|
def threshold_vs_intensity(adaptation_luminance):
|
|
log_lum = float('-inf') # Works in Python 2.6+
|
|
try:
|
|
log_lum = log10(adaptation_luminance)
|
|
except ValueError:
|
|
pass
|
|
|
|
x = 0.0
|
|
|
|
if log_lum < -3.94:
|
|
x = -2.86
|
|
|
|
elif log_lum < -1.44:
|
|
x = pow(0.405 * log_lum + 1.6, 2.18) - 2.86
|
|
|
|
elif log_lum < -0.0184:
|
|
x = log_lum - 0.395
|
|
|
|
elif log_lum < 1.9:
|
|
x = pow(0.249 * log_lum + 0.65, 2.7) - 0.72
|
|
|
|
else:
|
|
x = log_lum - 1.255
|
|
|
|
return pow(10.0, x)
|
|
|
|
|
|
# From Daly 1993
|
|
def visual_mask(contrast):
|
|
x = pow(392.498 * contrast, 0.7)
|
|
x = pow(0.0153 * x, 4.0)
|
|
return pow(1.0 + x, 0.25)
|
|
|
|
|
|
# float gCubeRootTable[]
|
|
CUBE_ROOT_ACCESS_FUNCTION = '''
|
|
static float get_cube_root(float value) {
|
|
SkASSERT(value >= 0.0f);
|
|
SkASSERT(value * 1023.0f < 1024.0f);
|
|
return gCubeRootTable[(int)(value * 1023.0f)];
|
|
}
|
|
'''
|
|
def generate_cube_root_table(stream):
|
|
print('static float gCubeRootTable[] = {', end='', file=stream)
|
|
for i in range(1024):
|
|
if i % 6 == 0:
|
|
print('\n ', end='', file=stream)
|
|
print("%.10f" % pow(i / 1024.0, 1.0 / 3.0), end='f,', file=stream)
|
|
print('\n};', end='', file=stream)
|
|
print(CUBE_ROOT_ACCESS_FUNCTION, file=stream)
|
|
|
|
|
|
# float gGammaTable[]
|
|
GAMMA_ACCESS_FUNCTION = '''
|
|
static float get_gamma(unsigned char value) {
|
|
return gGammaTable[value];
|
|
}
|
|
'''
|
|
def generate_gamma_table(stream):
|
|
print('static float gGammaTable[] = {', end='', file=stream)
|
|
for i in range(256):
|
|
if i % 6 == 0:
|
|
print('\n ', end='', file=stream)
|
|
print("%.10f" % pow(i / 255.0, 2.2), end='f,', file=stream)
|
|
print('\n};', end='', file=stream)
|
|
print(GAMMA_ACCESS_FUNCTION, file=stream)
|
|
|
|
|
|
# float gTVITable[]
|
|
TVI_ACCESS_FUNCTION = '''
|
|
static float get_threshold_vs_intensity(float value) {
|
|
SkASSERT(value >= 0.0f);
|
|
SkASSERT(value < 100.0f);
|
|
return gTVITable[(int)(value * 100.0f)];
|
|
}
|
|
'''
|
|
def generate_tvi_table(stream):
|
|
print('static float gTVITable[] = {', end='', file=stream)
|
|
for i in range(10000):
|
|
if i % 6 == 0:
|
|
print('\n ', end='', file=stream)
|
|
print("%.10f" % threshold_vs_intensity(i / 100.0), end='f,', file=stream)
|
|
print('\n};', end='', file=stream)
|
|
print(TVI_ACCESS_FUNCTION, file=stream)
|
|
|
|
|
|
# float gVisualMaskTable[]
|
|
VISUAL_MASK_DOMAIN = 4000
|
|
VISUAL_MASK_ACCESS_FUNCTION = '''
|
|
static float get_visual_mask(float value) {{
|
|
SkASSERT(value >= 0.0f);
|
|
SkASSERT(value < {}.0f);
|
|
return gVisualMaskTable[(int)value];
|
|
}}'''
|
|
def generate_visual_mask_table(stream):
|
|
print('static float gVisualMaskTable[] = {', end='', file=stream)
|
|
for i in range(VISUAL_MASK_DOMAIN):
|
|
if i % 6 == 0:
|
|
print('\n ', end='', file=stream)
|
|
print("%.10f" % visual_mask(i), end='f,', file=stream)
|
|
print('\n};', end='', file=stream)
|
|
print(VISUAL_MASK_ACCESS_FUNCTION.format(VISUAL_MASK_DOMAIN), file=stream)
|
|
|
|
|
|
def generate_lookup_tables(stream):
|
|
print(COPYRIGHT, file=stream)
|
|
print(HELP, file=stream)
|
|
print('namespace SkPMetricUtil {', file=stream)
|
|
generate_cube_root_table(stream)
|
|
generate_gamma_table(stream)
|
|
generate_tvi_table(stream)
|
|
generate_visual_mask_table(stream)
|
|
print('}', file=stream)
|
|
|
|
|
|
def main():
|
|
pmetric_util_out = open('SkPMetricUtil_generated.h', 'wb')
|
|
generate_lookup_tables(pmetric_util_out)
|
|
pmetric_util_out.close()
|
|
|
|
|
|
if __name__ == '__main__':
|
|
main()
|