2bb596a256
If README says "spaces, not tabs" and "braces go on separate lines", then be consistent about it before it gets normal to not respect those rules.
67 lines
2.4 KiB
C++
67 lines
2.4 KiB
C++
/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2003 University of Southern California
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*
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* This library is free software; you can redistribute it and/or
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* modify it either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is University of Southern
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* California.
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*
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* Contributor(s):
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* Carl D. Worth <cworth@cworth.org>
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* Kristian Høgsberg <krh@redhat.com>
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* Chris Wilson <chris@chris-wilson.co.uk>
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*/
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/* Unpremultiplies data and converts native endian ARGB => RGBA bytes */
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static void
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unpremultiply_data (png_structp /*png*/, png_row_infop row_info, png_bytep data)
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{
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unsigned int i;
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for (i = 0; i < row_info->rowbytes; i += 4)
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{
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uint8_t *b = &data[i];
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uint32_t pixel;
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uint8_t alpha;
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memcpy (&pixel, b, sizeof (uint32_t));
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alpha = (pixel & 0xff000000) >> 24;
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if (alpha == 0)
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{
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b[0] = b[1] = b[2] = b[3] = 0;
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}
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else
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{
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b[0] = (((pixel & 0xff0000) >> 16) * 255 + alpha / 2) / alpha;
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b[1] = (((pixel & 0x00ff00) >> 8) * 255 + alpha / 2) / alpha;
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b[2] = (((pixel & 0x0000ff) >> 0) * 255 + alpha / 2) / alpha;
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b[3] = alpha;
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}
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}
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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