#!/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 . 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(): ''' Divide all colour components by the value of the most prominent colour component for each colour ''' for i in range(i_size): m = max([abs(x) for x in (r_curve[i], g_curve[i], b_curve[i])]) if m != 0: for curve in (r_curve, g_curve, b_curve): curve[i] /= m 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)