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/* Shared code for cairo based loaders like svgload and pdfload.
*/
/*
This file is part of VIPS.
VIPS 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 program 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 program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/vips.h>
#include <vips/internal.h>
/* Convert from Cairo-style premultiplied BGRA to RGBA.
*
* See also openslide's argb2rgba().
*/
void
vips__premultiplied_bgra2rgba( guint32 * restrict p, int n )
{
int x;
for( x = 0; x < n; x++ ) {
guint32 bgra = GUINT32_FROM_BE( p[x] );
guint8 a = bgra & 0xff;
guint32 rgba;
if( a == 0 ||
a == 255 )
rgba =
(bgra & 0x00ff00ff) |
(bgra & 0x0000ff00) << 16 |
(bgra & 0xff000000) >> 16;
else
/* Undo premultiplication.
*/
rgba =
((255 * ((bgra >> 8) & 0xff) / a) << 24) |
((255 * ((bgra >> 16) & 0xff) / a) << 16) |
((255 * ((bgra >> 24) & 0xff) / a) << 8) |
a;
p[x] = GUINT32_TO_BE( rgba );
}
}
/* Unpremultiplied RGBA (vips convention) to cairo-style premul BGRA.
*/
void
vips__rgba2bgra_premultiplied( guint32 * restrict p, int n )
{
int x;
for( x = 0; x < n; x++ ) {
guint32 rgba = GUINT32_FROM_BE( p[x] );
guint8 a = rgba & 0xff;
guint32 bgra;
if( a == 0 )
bgra = 0;
else if( a == 255 )
bgra = (rgba & 0x00ff00ff) |
(rgba & 0x0000ff00) << 16 |
(rgba & 0xff000000) >> 16;
else {
int r = (rgba >> 24) & 0xff;
int g = (rgba >> 16) & 0xff;
int b = (rgba >> 8) & 0xff;
r = ((r * a) + 128) >> 8;
g = ((g * a) + 128) >> 8;
b = ((b * a) + 128) >> 8;
bgra = (b << 24) | (g << 16) | (r << 8) | a;
}
p[x] = GUINT32_TO_BE( bgra );
}
}
/* Convert from PDFium-style BGRA to RGBA.
*/
void
vips__bgra2rgba( guint32 * restrict p, int n )
{
int x;
for( x = 0; x < n; x++ ) {
guint32 bgra = GUINT32_FROM_BE( p[x] );
guint rgba;
/* Leave G and A, swap R and B.
*/
rgba =
(bgra & 0x00ff00ff) |
(bgra & 0x0000ff00) << 16 |
(bgra & 0xff000000) >> 16;
p[x] = GUINT32_TO_BE( rgba );
}
}
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