Mercurial > libervia-backend

annotate sat/tools/common/utils.py @ 3252:54934ee3f69c

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tools (image): added a guess_type method to guess media type: media type is guessed first from filename, then if it's not enough, the file is opened to try to guess type. If it still can be determined, None is returned.
author Goffi <goffi@goffi.org>
date Tue, 14 Apr 2020 20:29:37 +0200
parents 9d0df638c8b4
children 1649bbe8d07e
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 #!/usr/bin/env python3
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2
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3 # SàT: a XMPP client
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4 # Copyright (C) 2009-2020 Jérôme Poisson (goffi@goffi.org)
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5
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6 # This program is free software: you can redistribute it and/or modify
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7 # it under the terms of the GNU Affero General Public License as published by
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8 # the Free Software Foundation, either version 3 of the License, or
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9 # (at your option) any later version.
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11 # This program is distributed in the hope that it will be useful,
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12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 # GNU Affero General Public License for more details.
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16 # You should have received a copy of the GNU Affero General Public License
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17 # along with this program. If not, see <http://www.gnu.org/licenses/>.
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19 """Misc utils for both backend and frontends"""
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22 def per_luminance(red, green, blue):
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23 """Caculate the perceived luminance of a RGB color
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24
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25 @param red(int): 0-1 normalized value of red
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26 @param green(int): 0-1 normalized value of green
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27 @param blue(int): 0-1 normalized value of blue
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28 @return (float): 0-1 value of luminance (<0.5 is dark, else it's light)
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29 """
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30 # cf. https://stackoverflow.com/a/1855903, thanks Gacek
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32 return 0.299 * red + 0.587 * green + 0.114 * blue