#!/usr/bin/env python3
# Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import math
from colour import *
# /usr/share/blueshift
DATADIR = '.'
# Mapping input and output maximum values + 1
i_size = 2 ** 8
o_size = 2 ** 16
# Red, green and blue curves
r_curve = [i / (i_size - 1) for i in range(i_size)]
g_curve = [i / (i_size - 1) for i in range(i_size)]
b_curve = [i / (i_size - 1) for i in range(i_size)]
clip_result = True
'''
Set to `False` if you want to allow value overflow rather than clipping,
doing so can create visual artifacts
'''
def curves(r, g, b):
'''
Generate a tuple of curve–parameter pairs
@param r The red parameter
@param g The green parameter
@param b The blue parameter
@return `((r_curve, r), (g_curve, g), (b_curve, b))`
'''
return ((r_curve, r), (g_curve, g), (b_curve, b))
def series_d(temperature):
'''
Calculate the colour for a blackbody temperature
@param temperature:float The blackbody temperature in kelvins, must be inside [4000, 7000]
@return :(float, float, float) The red, green and blue components of the white point
'''
x = 0
ks = ((0.244063, 0), (0.09911, 1), (2.9678, 2), (-4.6070, 3))
if temperature > 7000:
ks = ((0.237040, 0), (0.24748, 1), (1.9018, 2), (-2.0064, 3))
for (k, d) in ks:
x += k * 10 ** (d * 3) / temperature ** d
y = 2.870 * x - 3.000 * x ** 2 - 0.275
return ciexy_to_srgb(x, y, 1.0)
def simple_whitepoint(temperature):
'''
Calculate the colour for a blackbody temperature using a simple, but inaccurate, algorithm
@param temperature:float The blackbody temperature in kelvins, not guaranteed for values outside [1000, 40000]
@return :(float, float, float) The red, green and blue components of the white point
'''
r, g, b = 1, 1, 1
temp = temperature / 100
if temp > 66:
temp -= 60
r = 1.292936186 * temp ** 0.1332047592
g = 1.129890861 * temp ** -0.0755148492
else:
g = 0.390081579 * math.log(temp) - 0.631841444
if temp <= 19:
b = 0
elif temp < 66:
b = 0.543206789 * math.log(temp - 10) - 1.196254089
return (r, g, b)
cmf_2deg_cache = None
def cmf_2deg(temperature):
'''
Calculate the colour for a blackbody temperature using raw CIE 1931 2 degree CMF data with interpolation
@param temperature:float The blackbody temperature in kelvins, clipped to [1000, 40000]
@return :(float, float, float) The red, green and blue components of the white point
'''
if cmf_2deg_cache is None:
with open(DATADIR + '/2deg', 'rb') as file:
cmf_2deg_cache = file.read()
cmf_2deg_cache.decode('utf-8', 'error').split('\n')
cmf_2deg_cache = [[float(x) for x in x_y.split(' ')] for x_y in cmf_2deg_cache]
temperature = min(max(0, temperature), 1000)
x, y = 0, 0
if (temp % 100) == 0:
(x, y) = temperature[(temp - 1000) // 100]
else:
temp -= 1000
(x1, y1) = temperature[temp // 100]
(x2, y2) = temperature[temp // 100 + 1]
temp = (temp % 100) / 100
x = x1 * temp + x2 * (1 - temp)
y = y1 * temp + y2 * (1 - temp)
return ciexy_to_srgb(x, y, 1.0)
cmf_10deg_cache = None
def cmf_10deg(temperature):
'''
Calculate the colour for a blackbody temperature using raw CIE 1964 10 degree CMF data with interpolation
@param temperature:float The blackbody temperature in kelvins, clipped to [1000, 40000]
@return :(float, float, float) The red, green and blue components of the white point
'''
if cmf_2deg_cache is None:
with open(DATADIR + '/10deg', 'rb') as file:
cmf_2deg_cache = file.read()
cmf_2deg_cache.decode('utf-8', 'error').split('\n')
cmf_2deg_cache = [[float(x) for x in x_y.split(' ')] for x_y in cmf_2deg_cache]
temperature = min(max(0, temperature), 1000)
x, y = 0, 0
if (temp % 100) == 0:
(x, y) = temperature[(temp - 1000) // 100]
else:
temp -= 1000
(x1, y1) = temperature[temp // 100]
(x2, y2) = temperature[temp // 100 + 1]
temp = (temp % 100) / 100
x = x1 * temp + x2 * (1 - temp)
y = y1 * temp + y2 * (1 - temp)
return ciexy_to_srgb(x, y, 1.0)
def temperature(temperature, algorithm, linear_rgb = True):
'''
Change colour temperature according to the CIE illuminant series D
@param temperature:float The blackbody temperature in kelvins
@param algorithm:(float)→(float, float, float) Algorithm for calculating a white point, for example `series_d` or `simple_whitepoint`
@param linear_rgb:[bool] Whether to use linear RGB, otherwise sRG is used
'''
if temperature == 6500:
return
(r, g, b) = algorithm(temperature)
if linear_rgb:
for curve in (r_curve, g_curve, b_curve):
for i in range(i_size):
R, G, B = r_curve[i], g_curve[i], b_curve[i]
(R, G, B) = standard_to_linear(R, G, B)
r_curve[i], g_curve[i], b_curve[i] = R, G, B
rgb_brightness(r, g, b)
if linear_rgb:
for curve in (r_curve, g_curve, b_curve):
for i in range(i_size):
R, G, B = r_curve[i], g_curve[i], b_curve[i]
(R, G, B) = linear_to_standard(R, G, B)
r_curve[i], g_curve[i], b_curve[i] = R, G, B
def divide_by_maximum(rgb):
'''
Divide all colour components by the value of the most prominent colour component
@param rgb:[float, float, float] The three colour components
@return :[float, float, float] The three colour components divided by the maximum
'''
m = max([abs(x) for x in rgb])
if m != 0:
return [x / m for x in rgb]
return rgb
def clip_whitepoint(rgb):
'''
Clip all colour components to fit inside [0, 1]
@param rgb:[float, float, float] The three colour components
@return :[float, float, float] The three colour components clipped
'''
return [min(max(0, x), 1) for x in rgb]
def rgb_contrast(r, g, b):
'''
Apply contrast correction on the colour curves using sRGB
@param r:float The contrast parameter for the red curve
@param g:float The contrast parameter for the green curve
@param b:float The contrast parameter for the blue curve
'''
for (curve, level) in curves(r, g, b):
if not level == 1.0:
for i in range(i_size):
curve[i] = (curve[i] - 0.5) * level + 0.5
def cie_contrast(level):
'''
Apply contrast correction on the colour curves using CIE XYZ
@param level:float The brightness parameter
'''
if not level == 1.0:
for i in range(i_size):
(x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i])
(r_curve[i], g_curve[i], b_curve[i]) = to_rgb(x, y, (Y - 0.5) * level + 0.5)
def rgb_brightness(r, g, b):
'''
Apply brightness correction on the colour curves using sRGB
@param r:float The brightness parameter for the red curve
@param g:float The brightness parameter for the green curve
@param b:float The brightness parameter for the blue curve
'''
for (curve, level) in curves(r, g, b):
if not level == 1.0:
for i in range(i_size):
curve[i] *= level
def cie_brightness(level):
'''
Apply brightness correction on the colour curves using CIE XYZ
@param level:float The brightness parameter
'''
if not level == 1.0:
for i in range(i_size):
(x, y, Y) = srgb_to_ciexyy(r_curve[i], g_curve[i], b_curve[i])
(r_curve[i], g_curve[i], b_curve[i]) = to_rgb(x, y, Y * level)
def gamma(r, g, b):
'''
Apply gamma correction on the colour curves
@param r:float The gamma parameter for the red curve
@param g:float The gamma parameter for the green curve
@param b:float The gamma parameter for the blue curve
'''
for (curve, level) in curves(r, g, b):
if not level == 1.0:
for i in range(i_size):
curve[i] **= level
def sigmoid(r, g, b):
'''
Apply S-curve correction on the colour curves
@param r:float? The sigmoid parameter for the red curve
@param g:float? The sigmoid parameter for the green curve
@param b:float? The sigmoid parameter for the blue curve
'''
for (curve, level) in curves(r, g, b):
if level is not None:
for i in range(i_size):
try:
curve[i] = 0.5 - math.log(1 / curve[i] - 1) / level
except:
curve[i] = 0;
def clip():
'''
Clip all values below the actual minimum and above actual maximums
'''
for curve in (r_curve, g_curve, b_curve):
for i in range(i_size):
curve[i] = min(max(0.0, curve[i]), 1.0)
