32 lines
927 B
C++
32 lines
927 B
C++
/*
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This file is part of Telegram Desktop,
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the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
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https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
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#include "ui/color_contrast.h"
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namespace Ui {
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// https://stackoverflow.com/a/9733420
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float64 CountContrast(const QColor &a, const QColor &b) {
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const auto luminance = [](const QColor &c) {
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const auto map = [](double value) {
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return (value <= 0.03928)
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? (value / 12.92)
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: std::pow((value + 0.055) / 1.055, 2.4);
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};
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return map(c.redF()) * 0.2126
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+ map(c.greenF()) * 0.7152
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+ map(c.blueF()) * 0.0722;
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};
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const auto luminance1 = luminance(a);
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const auto luminance2 = luminance(b);
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const auto brightest = std::max(luminance1, luminance2);
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const auto darkest = std::min(luminance1, luminance2);
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return (brightest + 0.05) / (darkest + 0.05);
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}
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} // namespace Ui
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