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91 lines
2.1 KiB
91 lines
2.1 KiB
15 years ago
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/*
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Copyright (C) 2003 KSVG Team
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This file is part of the KDE project
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include <math.h>
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#include "KSVGHelper.h"
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using namespace KSVG;
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bool KSVGHelper::m_initialised = false;
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int KSVGHelper::m_linearRGBFromsRGB[256];
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int KSVGHelper::m_sRGBFromLinearRGB[256];
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// Force initialisation of the lookup tables
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static KSVGHelper ksvgHelper;
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KSVGHelper::KSVGHelper()
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{
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if(!m_initialised)
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{
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initialise();
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m_initialised = true;
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}
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}
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void KSVGHelper::initialise()
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{
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// Set up linearRGB - sRGB conversion tables
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for(int i = 0; i < 256; i++)
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{
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m_linearRGBFromsRGB[i] = calcLinearRGBFromsRGB(i);
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m_sRGBFromLinearRGB[i] = calcSRGBFromLinearRGB(i);
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}
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}
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int KSVGHelper::calcLinearRGBFromsRGB(int sRGB8bit)
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{
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double sRGB = sRGB8bit / 255.0;
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double linearRGB;
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if(sRGB <= 0.04045)
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linearRGB = sRGB / 12.92;
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else
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linearRGB = pow((sRGB + 0.055) / 1.055, 2.4);
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return static_cast<int>(linearRGB * 255 + 0.5);
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}
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int KSVGHelper::calcSRGBFromLinearRGB(int linearRGB8bit)
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{
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double linearRGB = linearRGB8bit / 255.0;
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double sRGB;
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if(linearRGB <= 0.0031308)
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sRGB = linearRGB * 12.92;
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else
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sRGB = 1.055 * pow(linearRGB, 1 / 2.4) - 0.055;
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return static_cast<int>(sRGB * 255 + 0.5);
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}
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extern "C"
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int linearRGBFromsRGB(int sRGB8bit)
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{
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return KSVGHelper::linearRGBFromsRGB(sRGB8bit);
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}
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extern "C"
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int sRGBFromLinearRGB(int linearRGB8bit)
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{
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return KSVGHelper::sRGBFromLinearRGB(linearRGB8bit);
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}
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