ColorHelper.h

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/* ColorHelper.h - Helper methods for color related algorithms, etc.
 *
 * Copyright (c) 2024- Michael Gregorius
 *
 * This file is part of LMMS - https://lmms.io
 *
 * This program 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.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
#ifndef LMMS_GUI_COLOR_HELPER_H
#define LMMS_GUI_COLOR_HELPER_H
 
#include <cmath>
#include <QColor>
 
namespace lmms::gui
{
 
class ColorHelper
{
public:
    static QColor interpolateInRgb(const QColor& a, const QColor& b, float t)
    {
#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
        using ColorType = float;
#else
        using ColorType = qreal;
#endif
 
        ColorType ar, ag, ab, aa;
        a.getRgbF(&ar, &ag, &ab, &aa);
 
        ColorType br, bg, bb, ba;
        b.getRgbF(&br, &bg, &bb, &ba);
 
        const auto t2 = static_cast<ColorType>(t);
        const auto interH = std::lerp(ar, br, t2);
        const auto interS = std::lerp(ag, bg, t2);
        const auto interV = std::lerp(ab, bb, t2);
        const auto interA = std::lerp(aa, ba, t2);
 
        return QColor::fromRgbF(interH, interS, interV, interA);
    }
};
 
} // namespace lmms::gui
 
#endif // LMMS_GUI_COLOR_HELPER_H