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latte-dock/liblatte2/commontools.cpp
Michail Vourlakos b418923c03 move from luminas to brightness
--the luminas functions didnt work well
for all cases. Latte is now using brightness
functions as described at:

   https://www.w3.org/TR/AERT/#color-contrast

this patch fixes all cases mentioned in the bug
that Latte contrast identification did not work well

BUG: 402115
2018-12-25 20:20:06 +02:00

75 lines
1.9 KiB
C++

/*
* Copyright 2018 Michail Vourlakos <mvourlakos@gmail.com>
*
* This file is part of Latte-Dock
*
* Latte-Dock is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* Latte-Dock 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "commontools.h"
// Qt
#include <QtMath>
namespace Latte {
float colorBrightness(QColor color)
{
return colorBrightness(color.red(), color.green(), color.blue());
}
float colorBrightness(QRgb rgb)
{
return colorBrightness(qRed(rgb), qGreen(rgb), qBlue(rgb));
}
float colorBrightness(float r, float g, float b)
{
float brightness = (r * 299 + g * 587 + b * 114) / 1000;
return brightness;
}
float colorLumina(QRgb rgb)
{
float r = (float)(qRed(rgb)) / 255;
float g = (float)(qGreen(rgb)) / 255;
float b = (float)(qBlue(rgb)) / 255;
return colorLumina(r, g, b);
}
float colorLumina(QColor color)
{
return colorLumina(color.redF(), color.greenF(), color.blueF());
}
float colorLumina(float r, float g, float b)
{
// formula for luminance according to:
// https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
float rS = (r <= 0.03928 ? r / 12.92 : qPow(((r + 0.055) / 1.055), 2.4));
float gS = (g <= 0.03928 ? g / 12.92 : qPow(((g + 0.055) / 1.055), 2.4));
float bS = (b <= 0.03928 ? b / 12.92 : qPow(((b + 0.055) / 1.055), 2.4));
float luminosity = 0.2126 * rS + 0.7152 * gS + 0.0722 * bS;
return luminosity;
}
}