Tesseract  3.02
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points.cpp
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1 /**********************************************************************
2  * File: points.c (Formerly coords.c)
3  * Description: Member functions for coordinate classes.
4  * Author: Ray Smith
5  * Created: Fri Mar 15 08:58:17 GMT 1991
6  *
7  * (C) Copyright 1991, Hewlett-Packard Ltd.
8  ** Licensed under the Apache License, Version 2.0 (the "License");
9  ** you may not use this file except in compliance with the License.
10  ** You may obtain a copy of the License at
11  ** http://www.apache.org/licenses/LICENSE-2.0
12  ** Unless required by applicable law or agreed to in writing, software
13  ** distributed under the License is distributed on an "AS IS" BASIS,
14  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  ** See the License for the specific language governing permissions and
16  ** limitations under the License.
17  *
18  **********************************************************************/
19 
20 #include "mfcpch.h" //precompiled headers
21 #include <stdlib.h>
22 #include "helpers.h"
23 #include "ndminx.h"
24 #include "serialis.h"
25 #include "points.h"
26 
27 ELISTIZE (ICOORDELT) //turn to list
28 bool FCOORD::normalise() { //Convert to unit vec
29  float len = length ();
30 
31  if (len < 0.0000000001) {
32  return false;
33  }
34  xcoord /= len;
35  ycoord /= len;
36  return true;
37 }
38 
39 // Set from the given x,y, shrinking the vector to fit if needed.
40 void ICOORD::set_with_shrink(int x, int y) {
41  // Fit the vector into an ICOORD, which is 16 bit.
42  int factor = 1;
43  int max_extent = MAX(abs(x), abs(y));
44  if (max_extent > MAX_INT16)
45  factor = max_extent / MAX_INT16 + 1;
46  xcoord = x / factor;
47  ycoord = y / factor;
48 }
49 
50 // The fortran/basic sgn function returns -1, 0, 1 if x < 0, x == 0, x > 0
51 // respectively.
52 static int sign(int x) {
53  if (x < 0)
54  return -1;
55  else
56  return x > 0 ? 1 : 0;
57 }
58 
59 // Writes to the given file. Returns false in case of error.
60 bool ICOORD::Serialize(FILE* fp) const {
61  if (fwrite(&xcoord, sizeof(xcoord), 1, fp) != 1) return false;
62  if (fwrite(&ycoord, sizeof(ycoord), 1, fp) != 1) return false;
63  return true;
64 }
65 // Reads from the given file. Returns false in case of error.
66 // If swap is true, assumes a big/little-endian swap is needed.
67 bool ICOORD::DeSerialize(bool swap, FILE* fp) {
68  if (fread(&xcoord, sizeof(xcoord), 1, fp) != 1) return false;
69  if (fread(&ycoord, sizeof(ycoord), 1, fp) != 1) return false;
70  if (swap) {
71  ReverseN(&xcoord, sizeof(xcoord));
72  ReverseN(&ycoord, sizeof(ycoord));
73  }
74  return true;
75 }
76 
77 // Setup for iterating over the pixels in a vector by the well-known
78 // Bresenham rendering algorithm.
79 // Starting with major/2 in the accumulator, on each step add major_step,
80 // and then add minor to the accumulator. When the accumulator >= major
81 // subtract major and step a minor step.
82 
83 void ICOORD::setup_render(ICOORD* major_step, ICOORD* minor_step,
84  int* major, int* minor) const {
85  int abs_x = abs(xcoord);
86  int abs_y = abs(ycoord);
87  if (abs_x >= abs_y) {
88  // X-direction is major.
89  major_step->xcoord = sign(xcoord);
90  major_step->ycoord = 0;
91  minor_step->xcoord = 0;
92  minor_step->ycoord = sign(ycoord);
93  *major = abs_x;
94  *minor = abs_y;
95  } else {
96  // Y-direction is major.
97  major_step->xcoord = 0;
98  major_step->ycoord = sign(ycoord);
99  minor_step->xcoord = sign(xcoord);
100  minor_step->ycoord = 0;
101  *major = abs_y;
102  *minor = abs_x;
103  }
104 }