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/*Copyright (C) 2008-2009 Timothy B. Terriberry (tterribe@xiph.org)
You can redistribute this library and/or modify it under the terms of the
GNU Lesser General Public License as published by the Free Software
Foundation; either version 2.1 of the License, or (at your option) any later
version.*/
#ifndef _QRCODE_H_
#define _QRCODE_H_
#include <zbar.h>
typedef struct qr_reader qr_reader;
typedef int qr_point[2];
typedef struct qr_finder_line qr_finder_line;
/*The number of bits of subpel precision to store image coordinates in.
This helps when estimating positions in low-resolution images, which may have
a module pitch only a pixel or two wide, making rounding errors matter a
great deal.*/
#define QR_FINDER_SUBPREC (2)
/*A line crossing a finder pattern.
Whether the line is horizontal or vertical is determined by context.
The offsts to various parts of the finder pattern are as follows:
|*****| |*****|*****|*****| |*****|
|*****| |*****|*****|*****| |*****|
^ ^ ^ ^
| | | |
| | | pos[v]+len+eoffs
| | pos[v]+len
| pos[v]
pos[v]-boffs
Here v is 0 for horizontal and 1 for vertical lines.*/
struct qr_finder_line {
/*The location of the upper/left endpoint of the line.
The left/upper edge of the center section is used, since other lines must
cross in this region.*/
qr_point pos;
/*The length of the center section.
This extends to the right/bottom of the center section, since other lines
must cross in this region.*/
int len;
/*The offset to the midpoint of the upper/left section (part of the outside
ring), or 0 if we couldn't identify the edge of the beginning section.
We use the midpoint instead of the edge because it can be located more
reliably.*/
int boffs;
/*The offset to the midpoint of the end section (part of the outside ring),
or 0 if we couldn't identify the edge of the end section.
We use the midpoint instead of the edge because it can be located more
reliably.*/
int eoffs;
};
qr_reader *_zbar_qr_create(void);
void _zbar_qr_destroy(qr_reader *reader);
void _zbar_qr_reset(qr_reader *reader);
int _zbar_qr_found_line(qr_reader *reader, int direction,
const qr_finder_line *line);
int _zbar_qr_decode(qr_reader *reader, zbar_image_scanner_t *iscn,
zbar_image_t *img);
#endif
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