mutter/cogl/cogl-bitmap-fallback.c
Neil Roberts b9a9bf60b7 cogl-bitmap: Update the format after (un)premultiplying
The pixel format of the bitmap needs to have its premult flag cleared
or set after the premult conversion otherwise it may get converted
again.
2010-02-06 00:13:25 +00:00

431 lines
9.6 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-bitmap-private.h"
#include <string.h>
/* TO rgba */
inline static void
_cogl_g_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[0];
dst[1] = src[0];
dst[2] = src[0];
dst[3] = 255;
}
inline static void
_cogl_rgb_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = 255;
}
inline static void
_cogl_bgr_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = 255;
}
inline static void
_cogl_bgra_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = src[3];
}
inline static void
_cogl_argb_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[1];
dst[1] = src[2];
dst[2] = src[3];
dst[3] = src[0];
}
inline static void
_cogl_abgr_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[3];
dst[1] = src[2];
dst[2] = src[1];
dst[3] = src[0];
}
inline static void
_cogl_rgba_to_rgba (const guchar *src, guchar *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
}
/* FROM rgba */
inline static void
_cogl_rgba_to_g (const guchar *src, guchar *dst)
{
dst[0] = (src[0] + src[1] + src[2]) / 3;
}
inline static void
_cogl_rgba_to_rgb (const guchar *src, guchar *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
}
inline static void
_cogl_rgba_to_bgr (const guchar *src, guchar *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
}
inline static void
_cogl_rgba_to_bgra (const guchar *src, guchar *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = src[3];
}
inline static void
_cogl_rgba_to_argb (const guchar *src, guchar *dst)
{
dst[0] = src[3];
dst[1] = src[0];
dst[2] = src[1];
dst[3] = src[2];
}
inline static void
_cogl_rgba_to_abgr (const guchar *src, guchar *dst)
{
dst[0] = src[3];
dst[1] = src[2];
dst[2] = src[1];
dst[3] = src[0];
}
/* (Un)Premultiplication */
inline static void
_cogl_unpremult_alpha_0 (guchar *dst)
{
dst[0] = 0;
dst[1] = 0;
dst[2] = 0;
dst[3] = 0;
}
inline static void
_cogl_unpremult_alpha_last (guchar *dst)
{
guchar alpha = dst[3];
dst[0] = (dst[0] * 255) / alpha;
dst[1] = (dst[1] * 255) / alpha;
dst[2] = (dst[2] * 255) / alpha;
}
inline static void
_cogl_unpremult_alpha_first (guchar *dst)
{
guchar alpha = dst[0];
dst[1] = (dst[1] * 255) / alpha;
dst[2] = (dst[2] * 255) / alpha;
dst[3] = (dst[3] * 255) / alpha;
}
/* No division form of floor((c*a + 128)/255) (I first encountered
* this in the RENDER implementation in the X server.) Being exact
* is important for a == 255 - we want to get exactly c.
*/
#define MULT(d,a,t) \
G_STMT_START { \
t = d * a + 128; \
d = ((t >> 8) + t) >> 8; \
} G_STMT_END
inline static void
_cogl_premult_alpha_last (guchar *dst)
{
guchar alpha = dst[3];
/* Using a separate temporary per component has given slightly better
* code generation with GCC in the past; it shouldn't do any worse in
* any case.
*/
guint t1, t2, t3;
MULT(dst[0], alpha, t1);
MULT(dst[1], alpha, t2);
MULT(dst[2], alpha, t3);
}
inline static void
_cogl_premult_alpha_first (guchar *dst)
{
guchar alpha = dst[0];
guint t1, t2, t3;
MULT(dst[1], alpha, t1);
MULT(dst[2], alpha, t2);
MULT(dst[3], alpha, t3);
}
#undef MULT
gboolean
_cogl_bitmap_fallback_can_convert (CoglPixelFormat src, CoglPixelFormat dst)
{
if (src == dst)
return FALSE;
switch (src & COGL_UNORDERED_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
case COGL_PIXEL_FORMAT_24:
case COGL_PIXEL_FORMAT_32:
if ((dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_24 &&
(dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_32 &&
(dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_G_8)
return FALSE;
break;
default:
return FALSE;
}
return TRUE;
}
gboolean
_cogl_bitmap_fallback_can_unpremult (CoglPixelFormat format)
{
return ((format & COGL_UNORDERED_MASK) == COGL_PIXEL_FORMAT_32);
}
gboolean
_cogl_bitmap_fallback_can_premult (CoglPixelFormat format)
{
return ((format & COGL_UNORDERED_MASK) == COGL_PIXEL_FORMAT_32);
}
gboolean
_cogl_bitmap_fallback_convert (const CoglBitmap *bmp,
CoglBitmap *dst_bmp,
CoglPixelFormat dst_format)
{
guchar *src;
guchar *dst;
gint src_bpp;
gint dst_bpp;
gint x,y;
guchar temp_rgba[4] = {0,0,0,0};
/* Make sure conversion supported */
if (!_cogl_bitmap_fallback_can_convert (bmp->format, dst_format))
return FALSE;
src_bpp = _cogl_get_format_bpp (bmp->format);
dst_bpp = _cogl_get_format_bpp (dst_format);
/* Initialize destination bitmap */
*dst_bmp = *bmp;
dst_bmp->rowstride = sizeof(guchar) * dst_bpp * dst_bmp->width;
dst_bmp->format = ((bmp->format & COGL_PREMULT_BIT) |
(dst_format & COGL_UNPREMULT_MASK));
/* Allocate a new buffer to hold converted data */
dst_bmp->data = g_malloc (sizeof(guchar)
* dst_bmp->height
* dst_bmp->rowstride);
/* FIXME: Optimize */
for (y = 0; y < bmp->height; y++)
{
src = (guchar*)bmp->data + y * bmp->rowstride;
dst = (guchar*)dst_bmp->data + y * dst_bmp->rowstride;
for (x = 0; x < bmp->width; x++)
{
/* FIXME: Would be nice to at least remove this inner
* branching, but not sure it can be done without
* rewriting of the whole loop */
switch (bmp->format & COGL_UNPREMULT_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
_cogl_g_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_RGB_888:
_cogl_rgb_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_BGR_888:
_cogl_bgr_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_RGBA_8888:
_cogl_rgba_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_BGRA_8888:
_cogl_bgra_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_ARGB_8888:
_cogl_argb_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_ABGR_8888:
_cogl_abgr_to_rgba (src, temp_rgba); break;
default:
break;
}
switch (dst_format & COGL_UNPREMULT_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
_cogl_rgba_to_g (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_RGB_888:
_cogl_rgba_to_rgb (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_BGR_888:
_cogl_rgba_to_bgr (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_RGBA_8888:
_cogl_rgba_to_rgba (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_BGRA_8888:
_cogl_rgba_to_bgra (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_ARGB_8888:
_cogl_rgba_to_argb (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_ABGR_8888:
_cogl_rgba_to_abgr (temp_rgba, dst); break;
default:
break;
}
src += src_bpp;
dst += dst_bpp;
}
}
return TRUE;
}
gboolean
_cogl_bitmap_fallback_unpremult (CoglBitmap *bmp)
{
guchar *p;
gint x,y;
/* Make sure format supported for un-premultiplication */
if (!_cogl_bitmap_fallback_can_unpremult (bmp->format))
return FALSE;
for (y = 0; y < bmp->height; y++)
{
p = (guchar*) bmp->data + y * bmp->rowstride;
if (bmp->format & COGL_AFIRST_BIT)
{
for (x = 0; x < bmp->width; x++)
{
if (p[0] == 0)
_cogl_unpremult_alpha_0 (p);
else
_cogl_unpremult_alpha_first (p);
p += 4;
}
}
else
{
for (x = 0; x < bmp->width; x++)
{
if (p[3] == 0)
_cogl_unpremult_alpha_0 (p);
else
_cogl_unpremult_alpha_last (p);
p += 4;
}
}
}
bmp->format &= ~COGL_PREMULT_BIT;
return TRUE;
}
gboolean
_cogl_bitmap_fallback_premult (CoglBitmap *bmp)
{
guchar *p;
gint x,y;
/* Make sure format supported for un-premultiplication */
if (!_cogl_bitmap_fallback_can_premult (bmp->format))
return FALSE;
for (y = 0; y < bmp->height; y++)
{
p = (guchar*) bmp->data + y * bmp->rowstride;
if (bmp->format & COGL_AFIRST_BIT)
{
for (x = 0; x < bmp->width; x++)
{
_cogl_premult_alpha_first (p);
p += 4;
}
}
else
{
for (x = 0; x < bmp->width; x++)
{
_cogl_premult_alpha_last (p);
p += 4;
}
}
}
bmp->format |= COGL_PREMULT_BIT;
return TRUE;
}
gboolean
_cogl_bitmap_fallback_from_file (CoglBitmap *bmp,
const gchar *filename)
{
/* FIXME: use jpeglib, libpng, etc. manually maybe */
return FALSE;
}