1
2//----------------------------------------------------------------------------
3// Anti-Grain Geometry - Version 2.3
4// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
5//
6// Permission to copy, use, modify, sell and distribute this software
7// is granted provided this copyright notice appears in all copies.
8// This software is provided "as is" without express or implied
9// warranty, and with no claim as to its suitability for any purpose.
10//
11//----------------------------------------------------------------------------
12// Contact: mcseem@antigrain.com
13//          mcseemagg@yahoo.com
14//          http://www.antigrain.com
15//----------------------------------------------------------------------------
16// Bessel function (besj) was adapted for use in AGG library by Andy Wilk
17// Contact: castor.vulgaris@gmail.com
18//----------------------------------------------------------------------------
19#ifndef AGG_MATH_INCLUDED
20#define AGG_MATH_INCLUDED
21#include "agg_basics.h"
22namespace agg
23{
24const float intersection_epsilon = 1.0e-30f;
25AGG_INLINE float calc_point_location(float x1, float y1,
26                                        float x2, float y2,
27                                        float x,  float y)
28{
29  return ((x - x2) * (y2 - y1)) - ((y - y2) * (x2 - x1));
30}
31AGG_INLINE float calc_distance(float x1, float y1, float x2, float y2)
32{
33    float dx = x2 - x1;
34    float dy = y2 - y1;
35    return FXSYS_sqrt2(dx, dy);
36}
37AGG_INLINE float calc_line_point_distance(float x1, float y1,
38        float x2, float y2,
39        float x,  float y)
40{
41    float dx = x2 - x1;
42    float dy = y2 - y1;
43    float d = FXSYS_sqrt2(dx, dy);
44    if(d < intersection_epsilon) {
45        return calc_distance(x1, y1, x, y);
46    }
47    return ((x - x2) * dy / d) - ((y - y2) * dx / d);
48}
49AGG_INLINE bool calc_intersection(float ax, float ay, float bx, float by,
50                                  float cx, float cy, float dx, float dy,
51                                  float* x, float* y)
52{
53  float num = ((ay - cy) * (dx - cx)) - ((ax - cx) * (dy - cy));
54  float den = ((bx - ax) * (dy - cy)) - ((by - ay) * (dx - cx));
55  if (fabs(den) < intersection_epsilon) {
56    return false;
57    }
58    *x = ax + ((bx - ax) * num / den);
59    *y = ay + ((by - ay) * num / den);
60    return true;
61}
62}
63#endif
64