67 lines
1.6 KiB
C
67 lines
1.6 KiB
C
/* Shared code for cairo based loaders like svgload and pdfload.
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/vips.h>
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#include <vips/internal.h>
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/* Convert from ARGB to RGBA and undo premultiplication.
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*
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* See also openslide's argb2rgba().
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*/
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void
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vips__cairo2rgba( guint32 * restrict buf, int n )
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{
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int i;
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for( i = 0; i < n; i++ ) {
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guint32 * restrict p = buf + i;
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guint32 x = *p;
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guint8 a = x >> 24;
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VipsPel * restrict out = (VipsPel *) p;
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if( a == 255 )
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*p = GUINT32_TO_BE( (x << 8) | 255 );
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else if( a == 0 )
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*p = GUINT32_TO_BE( x << 8 );
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else {
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/* Undo premultiplication.
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*/
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out[0] = 255 * ((x >> 16) & 255) / a;
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out[1] = 255 * ((x >> 8) & 255) / a;
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out[2] = 255 * (x & 255) / a;
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out[3] = a;
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}
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}
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}
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