#!/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 = 'res' def series_d(temperature): ''' Calculate the colour for a blackbody temperature Using `lambda t : divide_by_maximum(series_d(t))` as the algorithm is better than just `series_d` @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 ciexyy_to_srgb(x, y, 1.0) def simple_whitepoint(temperature): ''' Calculate the colour for a blackbody temperature using a simple 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 Using `lambda t : divide_by_maximum(cmf_2deg(t))` as the algorithm is better than just `cmf_2deg` @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 ''' global cmf_2deg_cache if cmf_2deg_cache is None: with open(DATADIR + '/2deg', 'rb') as file: cmf_2deg_cache = file.read() cmf_2deg_cache = cmf_2deg_cache.decode('utf-8', 'error').split('\n') cmf_2deg_cache = filter(lambda x : not x == '', cmf_2deg_cache) cmf_2deg_cache = [[float(x) for x in x_y.split(' ')] for x_y in cmf_2deg_cache] temp = min(max(1000, temperature), 40000) x, y = 0, 0 if (temp % 100) == 0: (x, y) = cmf_2deg_cache[int((temp - 1000) // 100)] else: temp -= 1000 (x1, y1) = cmf_2deg_cache[int(temp // 100)] (x2, y2) = cmf_2deg_cache[int(temp // 100 + 1)] temp = (temp % 100) / 100 x = x1 * temp + x2 * (1 - temp) y = y1 * temp + y2 * (1 - temp) return ciexyy_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 Using `lambda t : divide_by_maximum(cmf_10deg(t))` as the algorithm is better than just `cmf_10deg` @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 ''' global cmf_10deg_cache if cmf_10deg_cache is None: with open(DATADIR + '/10deg', 'rb') as file: cmf_10deg_cache = file.read() cmf_10deg_cache = cmf_10deg_cache.decode('utf-8', 'error').split('\n') cmf_10deg_cache = filter(lambda x : not x == '', cmf_10deg_cache) cmf_10deg_cache = [[float(x) for x in x_y.split(' ')] for x_y in cmf_10deg_cache] temp = min(max(1000, temperature), 40000) x, y = 0, 0 if (temp % 100) == 0: (x, y) = cmf_10deg_cache[int((temp - 1000) // 100)] else: temp -= 1000 (x1, y1) = cmf_10deg_cache[int(temp // 100)] (x2, y2) = cmf_10deg_cache[int(temp // 100 + 1)] temp = (temp % 100) / 100 x = x1 * temp + x2 * (1 - temp) y = y1 * temp + y2 * (1 - temp) return ciexyy_to_srgb(x, y, 1) redshift_cache, redshift_old_cache = None, None def redshift(temperature, old_version = False, linear_interpolation = False): ''' Calculate the colour for a blackbody temperature using same data as in the program redshift @param temperature:float The blackbody temperature in kelvins, clipped to [1000, 25100] (100 more kelvins than in redshift) @param old_version:bool Whether to the method used in redshift<=1.8, in which case `temperature` is clipped to [1000, 10000] (1 more kelvin than in redshift) @param linear_interpolation:bool Whether to interpolate one linear RGB instead of sRGB @return :(float, float, float) The red, green and blue components of the white point ''' global redshift_cache, redshift_old_cache cache = None if not old_version: if redshift_cache is None: with open(DATADIR + '/redshift', 'rb') as file: redshift_cache = file.read() redshift_cache = redshift_cache.decode('utf-8', 'error').split('\n') redshift_cache = filter(lambda x : not x == '', redshift_cache) redshift_cache = [[float(x) for x in r_g_b.split(' ')] for r_g_b in redshift_cache] cache = redshift_cache else: if redshift_old_cache is None: with open(DATADIR + '/redshift_old', 'rb') as file: redshift_old_cache = file.read() redshift_old_cache = redshift_old_cache.decode('utf-8', 'error').split('\n') redshift_old_cache = filter(lambda x : not x == '', redshift_old_cache) redshift_old_cache = [[float(x) for x in r_g_b.split(' ')] for r_g_b in redshift_old_cache] cache = redshift_old_cache temp = min(max(1000, temperature), 10000 if old_version else 25100) r, g, b = 1, 1, 1 if (temp % 100) == 0: (r, g, b) = cache[int((temp - 1000) // 100)] else: temp -= 1000 (r1, g1, b1) = cache[int(temp // 100)] (r2, g2, b2) = cache[int(temp // 100 + 1)] temp = (temp % 100) / 100 if linear_interpolation: (r, g, b) = standard_to_linear(r, g, b) r = r1 * temp + r2 * (1 - temp) g = g1 * temp + g2 * (1 - temp) b = b1 * temp + b2 * (1 - temp) if linear_interpolation: (r, g, b) = linear_to_standard(r, g, b) return (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]