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/*
Copyright (C) 2003 KSVG Team
This file is part of the KDE project
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include <math.h>
#include "KSVGHelper.h"
using namespace KSVG;
bool KSVGHelper::m_initialised = false;
int KSVGHelper::m_linearRGBFromsRGB[256];
int KSVGHelper::m_sRGBFromLinearRGB[256];
// Force initialisation of the lookup tables
static KSVGHelper ksvgHelper;
KSVGHelper::KSVGHelper()
{
if(!m_initialised)
{
initialise();
m_initialised = true;
}
}
void KSVGHelper::initialise()
{
// Set up linearRGB - sRGB conversion tables
for(int i = 0; i < 256; i++)
{
m_linearRGBFromsRGB[i] = calcLinearRGBFromsRGB(i);
m_sRGBFromLinearRGB[i] = calcSRGBFromLinearRGB(i);
}
}
int KSVGHelper::calcLinearRGBFromsRGB(int sRGB8bit)
{
double sRGB = sRGB8bit / 255.0;
double linearRGB;
if(sRGB <= 0.04045)
linearRGB = sRGB / 12.92;
else
linearRGB = pow((sRGB + 0.055) / 1.055, 2.4);
return static_cast<int>(linearRGB * 255 + 0.5);
}
int KSVGHelper::calcSRGBFromLinearRGB(int linearRGB8bit)
{
double linearRGB = linearRGB8bit / 255.0;
double sRGB;
if(linearRGB <= 0.0031308)
sRGB = linearRGB * 12.92;
else
sRGB = 1.055 * pow(linearRGB, 1 / 2.4) - 0.055;
return static_cast<int>(sRGB * 255 + 0.5);
}
extern "C"
int linearRGBFromsRGB(int sRGB8bit)
{
return KSVGHelper::linearRGBFromsRGB(sRGB8bit);
}
extern "C"
int sRGBFromLinearRGB(int linearRGB8bit)
{
return KSVGHelper::sRGBFromLinearRGB(linearRGB8bit);
}
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