1
2 //----------------------------------------------------------------------------
3 // XYQ: 2006-01-22 Copied from AGG project.
4 // TODO: This file uses intensive floating point operations, so it's NOT suitable
5 // for platforms like Symbian OS. We need to change to FIX format.
6 //----------------------------------------------------------------------------
7 //----------------------------------------------------------------------------
8 // Anti-Grain Geometry - Version 2.3
9 // Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
10 //
11 // Permission to copy, use, modify, sell and distribute this software
12 // is granted provided this copyright notice appears in all copies.
13 // This software is provided "as is" without express or implied
14 // warranty, and with no claim as to its suitability for any purpose.
15 //
16 //----------------------------------------------------------------------------
17 // Contact: mcseem@antigrain.com
18 // mcseemagg@yahoo.com
19 // http://www.antigrain.com
20 //----------------------------------------------------------------------------
21
22 #include "agg_curves.h"
23 #include "agg_math.h"
24
25 namespace agg
26 {
27 const float curve_collinearity_epsilon = 1e-30f;
28 enum curve_recursion_limit_e { curve_recursion_limit = 16 };
init(float x1,float y1,float x2,float y2,float x3,float y3,float x4,float y4)29 void curve4_div::init(float x1, float y1,
30 float x2, float y2,
31 float x3, float y3,
32 float x4, float y4)
33 {
34 m_points.remove_all();
35 m_distance_tolerance_square = 1.0f / 4;
36 m_distance_tolerance_manhattan = 1.0f * 4;
37 bezier(x1, y1, x2, y2, x3, y3, x4, y4);
38 m_count = 0;
39 }
recursive_bezier(float x1,float y1,float x2,float y2,float x3,float y3,float x4,float y4,unsigned level)40 void curve4_div::recursive_bezier(float x1, float y1,
41 float x2, float y2,
42 float x3, float y3,
43 float x4, float y4,
44 unsigned level)
45 {
46 if(level > curve_recursion_limit) {
47 return;
48 }
49 float x12 = (x1 + x2) / 2;
50 float y12 = (y1 + y2) / 2;
51 float x23 = (x2 + x3) / 2;
52 float y23 = (y2 + y3) / 2;
53 float x34 = (x3 + x4) / 2;
54 float y34 = (y3 + y4) / 2;
55 float x123 = (x12 + x23) / 2;
56 float y123 = (y12 + y23) / 2;
57 float x234 = (x23 + x34) / 2;
58 float y234 = (y23 + y34) / 2;
59 float x1234 = (x123 + x234) / 2;
60 float y1234 = (y123 + y234) / 2;
61 float dx = x4 - x1;
62 float dy = y4 - y1;
63 float d2 = fabs(((x2 - x4) * dy) - ((y2 - y4) * dx));
64 float d3 = fabs(((x3 - x4) * dy) - ((y3 - y4) * dx));
65 switch((int(d2 > curve_collinearity_epsilon) << 1) +
66 int(d3 > curve_collinearity_epsilon)) {
67 case 0:
68 if (fabs(x1 + x3 - x2 - x2) + fabs(y1 + y3 - y2 - y2) +
69 fabs(x2 + x4 - x3 - x3) + fabs(y2 + y4 - y3 - y3) <=
70 m_distance_tolerance_manhattan) {
71 m_points.add(point_type(x1234, y1234, path_flags_jr));
72 return;
73 }
74 break;
75 case 1:
76 if ((d3 * d3) <=
77 (m_distance_tolerance_square * ((dx * dx) + (dy * dy)))) {
78 m_points.add(point_type(x23, y23, path_flags_jr));
79 return;
80 }
81 break;
82 case 2:
83 if ((d2 * d2) <=
84 (m_distance_tolerance_square * ((dx * dx) + (dy * dy)))) {
85 m_points.add(point_type(x23, y23, path_flags_jr));
86 return;
87 }
88 break;
89 case 3:
90 if (((d2 + d3) * (d2 + d3)) <=
91 (m_distance_tolerance_square * ((dx * dx) + (dy * dy)))) {
92 m_points.add(point_type(x23, y23, path_flags_jr));
93 return;
94 }
95 break;
96 }
97 recursive_bezier(x1, y1, x12, y12, x123, y123, x1234, y1234, level + 1);
98 recursive_bezier(x1234, y1234, x234, y234, x34, y34, x4, y4, level + 1);
99 }
bezier(float x1,float y1,float x2,float y2,float x3,float y3,float x4,float y4)100 void curve4_div::bezier(float x1, float y1,
101 float x2, float y2,
102 float x3, float y3,
103 float x4, float y4)
104 {
105 m_points.add(point_type(x1, y1));
106 recursive_bezier(x1, y1, x2, y2, x3, y3, x4, y4, 0);
107 m_points.add(point_type(x4, y4));
108 }
109 }
110