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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice 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 <basegfx/numeric/ftools.hxx>
#include <basegfx/color/bcolor.hxx>
#include <basegfx/color/bcolortools.hxx>
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) )
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();
}
}
}
} // end of namespace
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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