File indexing completed on 2023-12-03 07:42:26

 /*  This file is part of the KDE project
     SPDX-FileCopyrightText: 2007 Matthew Woehlke <mw_triad@users.sourceforge.net>
     SPDX-FileCopyrightText: 2007 Thomas Zander <zander@kde.org>
     SPDX-FileCopyrightText: 2007 Zack Rusin <zack@kde.org>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 #include "kcolorspaces_p.h"
 #include "kguiaddons_colorhelpers_p.h"
 #include <kcolorutils.h>
 
 #include <QColor>
 #include <QImage>
 #include <QtNumeric> // qIsNaN
 
 #include <math.h>
 
 // BEGIN internal helper functions
 static inline qreal mixQreal(qreal a, qreal b, qreal bias)
 {
     return a + (b - a) * bias;
 }
 // END internal helper functions
 
 qreal KColorUtils::hue(const QColor &color)
 {
     return KColorSpaces::KHCY::hue(color);
 }
 
 qreal KColorUtils::chroma(const QColor &color)
 {
     return KColorSpaces::KHCY::chroma(color);
 }
 
 qreal KColorUtils::luma(const QColor &color)
 {
     return KColorSpaces::KHCY::luma(color);
 }
 
 void KColorUtils::getHcy(const QColor &color, qreal *h, qreal *c, qreal *y, qreal *a)
 {
     if (!c || !h || !y) {
         return;
     }
     KColorSpaces::KHCY khcy(color);
     *c = khcy.c;
     *h = khcy.h + (khcy.h < 0.0 ? 1.0 : 0.0);
     *y = khcy.y;
     if (a) {
         *a = khcy.a;
     }
 }
 
 QColor KColorUtils::hcyColor(qreal h, qreal c, qreal y, qreal a)
 {
     return KColorSpaces::KHCY(h, c, y, a).qColor();
 }
 
 static qreal contrastRatioForLuma(qreal y1, qreal y2)
 {
     if (y1 > y2) {
         return (y1 + 0.05) / (y2 + 0.05);
     } else {
         return (y2 + 0.05) / (y1 + 0.05);
     }
 }
 
 qreal KColorUtils::contrastRatio(const QColor &c1, const QColor &c2)
 {
     return contrastRatioForLuma(luma(c1), luma(c2));
 }
 
 QColor KColorUtils::lighten(const QColor &color, qreal ky, qreal kc)
 {
     KColorSpaces::KHCY c(color);
     c.y = 1.0 - normalize((1.0 - c.y) * (1.0 - ky));
     c.c = 1.0 - normalize((1.0 - c.c) * kc);
     return c.qColor();
 }
 
 QColor KColorUtils::darken(const QColor &color, qreal ky, qreal kc)
 {
     KColorSpaces::KHCY c(color);
     c.y = normalize(c.y * (1.0 - ky));
     c.c = normalize(c.c * kc);
     return c.qColor();
 }
 
 QColor KColorUtils::shade(const QColor &color, qreal ky, qreal kc)
 {
     KColorSpaces::KHCY c(color);
     c.y = normalize(c.y + ky);
     c.c = normalize(c.c + kc);
     return c.qColor();
 }
 
 static QColor tintHelper(const QColor &base, qreal baseLuma, const QColor &color, qreal amount)
 {
     KColorSpaces::KHCY result(KColorUtils::mix(base, color, pow(amount, 0.3)));
     result.y = mixQreal(baseLuma, result.y, amount);
 
     return result.qColor();
 }
 
 QColor KColorUtils::tint(const QColor &base, const QColor &color, qreal amount)
 {
     if (amount <= 0.0) {
         return base;
     }
     if (amount >= 1.0) {
         return color;
     }
     if (qIsNaN(amount)) {
         return base;
     }
 
     qreal baseLuma = luma(base); // cache value because luma call is expensive
     double ri = contrastRatioForLuma(baseLuma, luma(color));
     double rg = 1.0 + ((ri + 1.0) * amount * amount * amount);
     double u = 1.0;
     double l = 0.0;
     QColor result;
     for (int i = 12; i; --i) {
         double a = 0.5 * (l + u);
         result = tintHelper(base, baseLuma, color, a);
         double ra = contrastRatioForLuma(baseLuma, luma(result));
         if (ra > rg) {
             u = a;
         } else {
             l = a;
         }
     }
     return result;
 }
 
 QColor KColorUtils::mix(const QColor &c1, const QColor &c2, qreal bias)
 {
     if (bias <= 0.0) {
         return c1;
     }
     if (bias >= 1.0) {
         return c2;
     }
     if (qIsNaN(bias)) {
         return c1;
     }
 
     qreal a = mixQreal(c1.alphaF(), c2.alphaF(), bias);
     if (a <= 0.0) {
         return Qt::transparent;
     }
 
     qreal r = qBound(0.0, mixQreal(c1.redF() * c1.alphaF(), c2.redF() * c2.alphaF(), bias), 1.0) / a;
     qreal g = qBound(0.0, mixQreal(c1.greenF() * c1.alphaF(), c2.greenF() * c2.alphaF(), bias), 1.0) / a;
     qreal b = qBound(0.0, mixQreal(c1.blueF() * c1.alphaF(), c2.blueF() * c2.alphaF(), bias), 1.0) / a;
 
     return QColor::fromRgbF(r, g, b, a);
 }
 
 QColor KColorUtils::overlayColors(const QColor &base, const QColor &paint, QPainter::CompositionMode comp)
 {
     // This isn't the fastest way, but should be "fast enough".
     // It's also the only safe way to use QPainter::CompositionMode
     QImage img(1, 1, QImage::Format_ARGB32_Premultiplied);
     QPainter p(&img);
     QColor start = base;
     start.setAlpha(255); // opaque
     p.fillRect(0, 0, 1, 1, start);
     p.setCompositionMode(comp);
     p.fillRect(0, 0, 1, 1, paint);
     p.end();
     return img.pixel(0, 0);
 }