4d3df8b3e3
Updated copyright to LGPL version 2.1 and year 2010 --HG-- extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%404453
60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*
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SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2010 Sam Lantinga
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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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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#include "SDL_blit.h"
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#include "SDL_alphamult.h"
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/* Functions to pre-multiply the alpha channel into the color channels */
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#define DEFINE_PREMULTIPLY_FUNC(fmt) \
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void \
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SDL_PreMultiplyAlpha##fmt(int w, int h, Uint32 *pixels, int pitch) \
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{ \
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pitch /= 4; \
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while (h--) { \
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int n; \
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Uint32 *row = pixels; \
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Uint32 pixel; \
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unsigned r, g, b, a; \
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\
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for (n = w; n--; ) { \
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pixel = *row; \
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RGBA_FROM_##fmt(pixel, r, g, b, a); \
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r = (r * a) / 255; \
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g = (g * a) / 255; \
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b = (b * a) / 255; \
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fmt##_FROM_RGBA(*row, r, g, b, a); \
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++row; \
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} \
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pixels += pitch; \
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} \
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}
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/* *INDENT-OFF* */
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DEFINE_PREMULTIPLY_FUNC(ARGB8888)
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DEFINE_PREMULTIPLY_FUNC(RGBA8888)
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DEFINE_PREMULTIPLY_FUNC(ABGR8888)
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DEFINE_PREMULTIPLY_FUNC(BGRA8888)
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/* *INDENT-ON* */
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/* vi: set ts=4 sw=4 expandtab: */
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