genode/repos/os/include/os/pixel_alpha8.h
Norman Feske cb72784717 os: add template specialization for alpha pixel
The specialization is needed for applying anti-aliased drawing
operations on alpha channels.
2017-08-28 16:49:39 +02:00

46 lines
1.0 KiB
C++

/*
* \brief Template specializations for the ALPHA8 pixel format
* \author Norman Feske
* \date 2014-09-10
*/
/*
* Copyright (C) 2014-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__OS__PIXEL_ALPHA8_H_
#define _INCLUDE__OS__PIXEL_ALPHA8_H_
#include <os/pixel_rgba.h>
namespace Genode {
typedef Genode::Pixel_rgba<unsigned char, Genode::Surface_base::ALPHA8,
0, 0, 0, 0, 0, 0, 0xff, 0>
Pixel_alpha8;
/*
* The second pixel parameter is ignored. It can be of any pixel type.
*/
template <>
template <typename PT>
inline Pixel_alpha8 Pixel_alpha8::mix(Pixel_alpha8 p1, PT, int alpha)
{
Pixel_alpha8 res;
res.pixel = p1.pixel + (((255 - p1.pixel)*alpha) >> 8);
return res;
}
template <>
inline Pixel_alpha8 Pixel_alpha8::mix(Pixel_alpha8 p1, Pixel_alpha8 p2, int alpha)
{
return mix<Pixel_alpha8>(p1, p2, alpha);
}
}
#endif /* _INCLUDE__OS__PIXEL_ALPHA8_H_ */