/*
* Copyright (c) 2008, Google Inc. All rights reserved.
* Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
* Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "platform/graphics/ColorSpace.h"
#include "wtf/MathExtras.h"
namespace WebCore {
namespace ColorSpaceUtilities {
static const uint8_t* getLinearRgbLUT()
{
static uint8_t linearRgbLUT[256];
static bool initialized;
if (!initialized) {
for (unsigned i = 0; i < 256; i++) {
float color = i / 255.0f;
color = (color <= 0.04045f ? color / 12.92f : pow((color + 0.055f) / 1.055f, 2.4f));
color = std::max(0.0f, color);
color = std::min(1.0f, color);
linearRgbLUT[i] = static_cast<uint8_t>(round(color * 255));
}
initialized = true;
}
return linearRgbLUT;
}
static const uint8_t* getDeviceRgbLUT()
{
static uint8_t deviceRgbLUT[256];
static bool initialized;
if (!initialized) {
for (unsigned i = 0; i < 256; i++) {
float color = i / 255.0f;
color = (powf(color, 1.0f / 2.4f) * 1.055f) - 0.055f;
color = std::max(0.0f, color);
color = std::min(1.0f, color);
deviceRgbLUT[i] = static_cast<uint8_t>(round(color * 255));
}
initialized = true;
}
return deviceRgbLUT;
}
const uint8_t* getConversionLUT(ColorSpace dstColorSpace, ColorSpace srcColorSpace)
{
// Identity.
if (srcColorSpace == dstColorSpace)
return 0;
// Only sRGB/DeviceRGB <-> linearRGB are supported at the moment.
if ((srcColorSpace != ColorSpaceLinearRGB && srcColorSpace != ColorSpaceDeviceRGB)
|| (dstColorSpace != ColorSpaceLinearRGB && dstColorSpace != ColorSpaceDeviceRGB))
return 0;
if (dstColorSpace == ColorSpaceLinearRGB)
return getLinearRgbLUT();
if (dstColorSpace == ColorSpaceDeviceRGB)
return getDeviceRgbLUT();
ASSERT_NOT_REACHED();
return 0;
}
Color convertColor(const Color& srcColor, ColorSpace dstColorSpace, ColorSpace srcColorSpace)
{
const uint8_t* lookupTable = getConversionLUT(dstColorSpace, srcColorSpace);
if (!lookupTable)
return srcColor;
return Color(lookupTable[srcColor.red()], lookupTable[srcColor.green()], lookupTable[srcColor.blue()], srcColor.alpha());
}
} // namespace ColorSpaceUtilities
} // namespace WebCore