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Diffstat (limited to 'src/blackbody.py')
| -rw-r--r-- | src/blackbody.py | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/blackbody.py b/src/blackbody.py new file mode 100644 index 0000000..42fc6ff --- /dev/null +++ b/src/blackbody.py @@ -0,0 +1,201 @@ +#!/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] + |