107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
/*------------------------------------------------------------------------
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* Copyright 2009-2010 (c) Jeff Brown <spadix@users.sourceforge.net>
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*
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* This file is part of the ZBar Bar Code Reader.
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*
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* The ZBar Bar Code Reader is free software; you can redistribute it
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* and/or modify it under the terms of the GNU Lesser Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* The ZBar Bar Code Reader is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser Public License for more details.
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*
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* You should have received a copy of the GNU Lesser Public License
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* along with the ZBar Bar Code Reader; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301 USA
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*
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* http://sourceforge.net/projects/zbar
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*------------------------------------------------------------------------*/
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#include <zbar_config.h>
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#include <assert.h>
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#include <zbar.h>
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#ifdef DEBUG_QR_FINDER
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# define DEBUG_LEVEL (DEBUG_QR_FINDER)
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#endif
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#include "debug.h"
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#include "decoder.h"
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/* at this point lengths are all decode unit offsets from the decode edge
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* NB owned by finder
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*/
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qr_finder_line *_zbar_decoder_get_qr_finder_line (zbar_decoder_t *dcode)
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{
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return(&dcode->qrf.line);
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}
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zbar_symbol_type_t _zbar_find_qr (zbar_decoder_t *dcode)
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{
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qr_finder_t *qrf = &dcode->qrf;
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unsigned s, qz, w;
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int ei;
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/* update latest finder pattern width */
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qrf->s5 -= get_width(dcode, 6);
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qrf->s5 += get_width(dcode, 1);
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s = qrf->s5;
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/*TODO: The 2005 standard allows reflectance-reversed codes (light on dark
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instead of dark on light).
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If we find finder patterns with the opposite polarity, we should invert
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the final binarized image and use them to search for QR codes in that.*/
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if(get_color(dcode) != ZBAR_SPACE || s < 7)
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return(0);
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dbprintf(2, " qrf: s=%d", s);
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ei = decode_e(pair_width(dcode, 1), s, 7);
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dbprintf(2, " %d", ei);
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if(ei)
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goto invalid;
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ei = decode_e(pair_width(dcode, 2), s, 7);
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dbprintf(2, "%d", ei);
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if(ei != 2)
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goto invalid;
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ei = decode_e(pair_width(dcode, 3), s, 7);
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dbprintf(2, "%d", ei);
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if(ei != 2)
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goto invalid;
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ei = decode_e(pair_width(dcode, 4), s, 7);
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dbprintf(2, "%d", ei);
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if(ei)
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goto invalid;
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/* valid QR finder symbol
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* mark positions needed by decoder
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*/
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qz = get_width(dcode, 0);
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w = get_width(dcode, 1);
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qrf->line.eoffs = qz + (w + 1) / 2;
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qrf->line.len = qz + w + get_width(dcode, 2);
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qrf->line.pos[0] = qrf->line.len + get_width(dcode, 3);
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qrf->line.pos[1] = qrf->line.pos[0];
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w = get_width(dcode, 5);
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qrf->line.boffs = qrf->line.pos[0] + get_width(dcode, 4) + (w + 1) / 2;
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dbprintf(2, " boff=%d pos=%d len=%d eoff=%d [valid]\n",
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qrf->line.boffs, qrf->line.pos[0], qrf->line.len,
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qrf->line.eoffs);
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dcode->direction = 0;
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dcode->buflen = 0;
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return(ZBAR_QRCODE);
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invalid:
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dbprintf(2, " [invalid]\n");
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return(0);
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}
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