/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ /* * This file is part of the Collabora Office project. * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. * * This file incorporates work covered by the following license notice: * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed * with this work for additional information regarding copyright * ownership. The ASF licenses this file to you under the Apache * License, Version 2.0 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.apache.org/licenses/LICENSE-2.0 . */ #include #include #include #include namespace basegfx::utils { BColor rgb2hsl(const BColor& rRGBColor) { const double r=rRGBColor.getRed(), g=rRGBColor.getGreen(), b=rRGBColor.getBlue(); const double minVal = std::min( std::min( r, g ), b ); const double maxVal = std::max( std::max( r, g ), b ); const double d = maxVal - minVal; double h=0, s=0, l=0; l = (maxVal + minVal) / 2.0; if( ::basegfx::fTools::equalZero(d) ) { s = h = 0; // hue undefined (achromatic case) } else { s = l > 0.5 ? d/(2.0-maxVal-minVal) : d/(maxVal + minVal); if( rtl::math::approxEqual(r, maxVal) ) h = (g - b)/d; else if( rtl::math::approxEqual(g, maxVal) ) h = 2.0 + (b - r)/d; else h = 4.0 + (r - g)/d; h *= 60.0; if( h < 0.0 ) h += 360.0; } return BColor(h,s,l); } static double hsl2rgbHelper( double nValue1, double nValue2, double nHue ) { // clamp hue to [0,360] nHue = fmod( nHue, 360.0 ); // cope with wrap-arounds if( nHue < 0.0 ) nHue += 360.0; if( nHue < 60.0 ) return nValue1 + (nValue2 - nValue1)*nHue/60.0; else if( nHue < 180.0 ) return nValue2; else if( nHue < 240.0 ) return nValue1 + (nValue2 - nValue1)*(240.0 - nHue)/60.0; else return nValue1; } BColor hsl2rgb(const BColor& rHSLColor) { const double h=rHSLColor.getRed(), s=rHSLColor.getGreen(), l=rHSLColor.getBlue(); if( fTools::equalZero(s) ) return BColor(l, l, l ); // achromatic case const double nVal1( l <= 0.5 ? l*(1.0 + s) : l + s - l*s ); const double nVal2( 2.0*l - nVal1 ); return BColor( hsl2rgbHelper(nVal2, nVal1, h + 120.0), hsl2rgbHelper(nVal2, nVal1, h), hsl2rgbHelper(nVal2, nVal1, h - 120.0) ); } BColor rgb2hsv(const BColor& rRGBColor) { const double r=rRGBColor.getRed(), g=rRGBColor.getGreen(), b=rRGBColor.getBlue(); const double maxVal = std::max(std::max(r,g),b); const double minVal = std::min(std::min(r,g),b); const double delta = maxVal-minVal; double h=0, s=0, v=0; v = maxVal; if( fTools::equalZero(v) ) s = 0; else s = delta / v; if( !fTools::equalZero(s) ) { if( rtl::math::approxEqual(maxVal, r) ) { h = (g - b) / delta; } else if( rtl::math::approxEqual(maxVal, g) ) { h = 2.0 + (b - r) / delta; } else { h = 4.0 + (r - g) / delta; } h *= 60.0; if( h < 0 ) h += 360; } return BColor(h,s,v); } BColor hsv2rgb(const BColor& rHSVColor) { double h=rHSVColor.getRed(); const double s=rHSVColor.getGreen(), v=rHSVColor.getBlue(); if( fTools::equalZero(s) ) { // achromatic case: no hue. return BColor(v,v,v); } else { if( fTools::equal(h, 360.0) ) h = 0; // 360 degrees is equivalent to 0 degrees h /= 60.0; const sal_Int32 intval = static_cast< sal_Int32 >( h ); const double f = h - intval; const double p = v*(1.0-s); const double q = v*(1.0-(s*f)); const double t = v*(1.0-(s*(1.0-f))); /* which hue area? */ switch( intval ) { case 0: return BColor(v,t,p); case 1: return BColor(q,v,p); case 2: return BColor(p,v,t); case 3: return BColor(p,q,v); case 4: return BColor(t,p,v); case 5: return BColor(v,p,q); default: // hue overflow return BColor(); } } } BColor convertSRGBToLinearRGB(const BColor& rRGB) { auto convert = [](double nValue) { return (nValue < 0.04045) ? (nValue / 12.92) : std::pow((nValue + 0.055) / 1.055, 2.4); }; return BColor(convert(rRGB.getRed()), convert(rRGB.getGreen()), convert(rRGB.getBlue())); } BColor convertLinearRGBToSRGB(const BColor& rLinearRGB) { auto convert = [](double nValue) { return (nValue <= 0.0031308) ? (nValue * 12.92) : (1.055 * std::pow(nValue, 1.0 / 2.4) - 0.055); }; return BColor(convert(rLinearRGB.getRed()), convert(rLinearRGB.getGreen()), convert(rLinearRGB.getBlue())); } BColor getLightVariant(BColor aColor) { // Sanitize input: clamp each channel to [0, 1]. aColor.clamp(); // Saturation in sRGB space, used to set the luminance cap. // Highly saturated colors get a lower cap so they don't wash out to white. double maxChannel = std::max({ aColor.getRed(), aColor.getGreen(), aColor.getBlue() }); double minChannel = std::min({ aColor.getRed(), aColor.getGreen(), aColor.getBlue() }); double saturation = (maxChannel < 0.001) ? 0.0 : (maxChannel - minChannel) / maxChannel; BColor aLinear = convertSRGBToLinearRGB(aColor); double Y = aColor.getWCAGLuminance(); // L_max: max output luminance. Goes from L_max_max for gray colors down to // L_max_min for highly saturated colors. const double L_max_max = 1.0; const double L_max_min = 0.50; const double L_max = L_max_max - (saturation * (L_max_max - L_max_min)); // L_min: min output luminance. const double L_min = 0.50; // Flip the input luminance [0, 1] into the range [L_max, L_min]. // Dark input becomes bright, bright input becomes darker. double Y_target = L_max - (Y * (L_max - L_min)); double r, g, b; if (Y < 0.001) { r = g = b = Y_target; } else { // Scale each channel by the same ratio to reach the target luminance. double ratio = Y_target / Y; r = aLinear.getRed() * ratio; g = aLinear.getGreen() * ratio; b = aLinear.getBlue() * ratio; } // If a channel went above 1.0, desaturate just enough to bring the // brightest channel back to 1.0 while preserving the hue. double max_c = std::max({ r, g, b }); if (max_c > 1.0) { double desaturate = (1.0 - Y_target) / (max_c - Y_target); r = Y_target + (r - Y_target) * desaturate; g = Y_target + (g - Y_target) * desaturate; b = Y_target + (b - Y_target) * desaturate; } return convertLinearRGBToSRGB(BColor(r, g, b)); } } // end of namespace /* vim:set shiftwidth=4 softtabstop=4 expandtab: */