#!/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 manipulate(r, g = None, b = None):
'''
Manipulate the colour curves using a lambda function
@param r:(float)→float Lambda function to manipulate the red colour curve
@param g:(float)?→float Lambda function to manipulate the green colour curve, defaults to `r` if `None`
@param b:(float)?→float Lambda function to manipulate the blue colour curve, defaults to `r` if `None`
The lambda functions thats a colour value and maps it to a new colour value.
For example, if the red value 0.5 is already mapped to 0.25, then if the function
maps 0.25 to 0.5, the red value 0.5 will revert back to being mapped to 0.5.
'''
if g is None: g = r
if b is None: b = r
for (curve, f) in curves(r, g, b):
for i in range(i_size):
curve[i] = f(curve[i])
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)
