tesseract  4.1.1
outlines.cpp
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1 /* -*-C-*-
2  ********************************************************************************
3  *
4  * File: outlines.cpp (Formerly outlines.c)
5  * Description: Combinatorial Splitter
6  * Author: Mark Seaman, OCR Technology
7  *
8  * (c) Copyright 1989, Hewlett-Packard Company.
9  ** Licensed under the Apache License, Version 2.0 (the "License");
10  ** you may not use this file except in compliance with the License.
11  ** You may obtain a copy of the License at
12  ** http://www.apache.org/licenses/LICENSE-2.0
13  ** Unless required by applicable law or agreed to in writing, software
14  ** distributed under the License is distributed on an "AS IS" BASIS,
15  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  ** See the License for the specific language governing permissions and
17  ** limitations under the License.
18  *
19  ********************************************************************************
20  * Revision 1.2 89/09/15 09:24:41 09:24:41 marks (Mark Seaman)
21  * First released version of Combinatorial splitter code
22  **/
23 /*----------------------------------------------------------------------
24  I n c l u d e s
25 ----------------------------------------------------------------------*/
26 #include "outlines.h"
27 #include "wordrec.h"
28 
29 namespace tesseract {
30 /*----------------------------------------------------------------------
31  F u n c t i o n s
32 ----------------------------------------------------------------------*/
33 /**********************************************************************
34  * near_point
35  *
36  * Find the point on a line segment that is closest to a point not on
37  * the line segment. Return that point in near_pt. Returns whether
38  * near_pt was newly created.
39  **********************************************************************/
41  EDGEPT *line_pt_0, EDGEPT *line_pt_1,
42  EDGEPT **near_pt) {
43  TPOINT p;
44 
45  float slope;
46  float intercept;
47 
48  float x0 = line_pt_0->pos.x;
49  float x1 = line_pt_1->pos.x;
50  float y0 = line_pt_0->pos.y;
51  float y1 = line_pt_1->pos.y;
52 
53  if (x0 == x1) {
54  /* Handle vertical line */
55  p.x = static_cast<int16_t>(x0);
56  p.y = point->pos.y;
57  }
58  else {
59  /* Slope and intercept */
60  slope = (y0 - y1) / (x0 - x1);
61  intercept = y1 - x1 * slope;
62 
63  /* Find perpendicular */
64  p.x = static_cast<int16_t>((point->pos.x + (point->pos.y - intercept) * slope) /
65  (slope * slope + 1));
66  p.y = static_cast<int16_t>(slope * p.x + intercept);
67  }
68 
69  if (is_on_line (p, line_pt_0->pos, line_pt_1->pos) &&
70  (!same_point (p, line_pt_0->pos)) && (!same_point (p, line_pt_1->pos))) {
71  /* Intersection on line */
72  *near_pt = make_edgept(p.x, p.y, line_pt_1, line_pt_0);
73  return true;
74  } else { /* Intersection not on line */
75  *near_pt = closest(point, line_pt_0, line_pt_1);
76  return false;
77  }
78 }
79 
80 } // namespace tesseract
EDGEPT * make_edgept(int x, int y, EDGEPT *next, EDGEPT *prev)
Definition: split.cpp:139
#define same_point(p1, p2)
Definition: outlines.h:45
#define is_on_line(p, p0, p1)
Definition: outlines.h:116
#define closest(test_p, p1, p2)
Definition: outlines.h:67
Definition: blobs.h:51
int16_t x
Definition: blobs.h:93
int16_t y
Definition: blobs.h:94
Definition: blobs.h:99
TPOINT pos
Definition: blobs.h:186
bool near_point(EDGEPT *point, EDGEPT *line_pt_0, EDGEPT *line_pt_1, EDGEPT **near_pt)
Definition: outlines.cpp:40