d4bf063788
- a new `utils` module has been added for backend and frontends generic utilities - per_luminance method calculate the perceived luminance of a colour (is it dark or light?). This is useful to automatically select the suitable colour in a theme.
32 lines
1.2 KiB
Python
32 lines
1.2 KiB
Python
#!/usr/bin/env python3
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# SàT: a XMPP client
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# Copyright (C) 2009-2019 Jérôme Poisson (goffi@goffi.org)
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""Misc utils for both backend and frontends"""
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def per_luminance(red, green, blue):
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"""Caculate the perceived luminance of a RGB color
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@param red(int): 0-1 normalized value of red
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@param green(int): 0-1 normalized value of green
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@param blue(int): 0-1 normalized value of blue
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@return (float): 0-1 value of luminance (<0.5 is dark, else it's light)
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"""
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# cf. https://stackoverflow.com/a/1855903, thanks Gacek
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return 0.299 * red + 0.587 * green + 0.114 * blue
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