1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.3
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//----------------------------------------------------------------------------
//
// Arc generator. Produces at most 4 consecutive cubic bezier curves, i.e.,
// 4, 7, 10, or 13 vertices.
//
//----------------------------------------------------------------------------
#ifndef AGG_BEZIER_ARC_INCLUDED
#define AGG_BEZIER_ARC_INCLUDED
#include "agg_conv_transform.h"
namespace agg
{
//-----------------------------------------------------------------------
void arc_to_bezier(double cx, double cy, double rx, double ry,
double start_angle, double sweep_angle,
double* curve);
//==============================================================bezier_arc
//
// See implemantaion agg_bezier_arc.cpp
//
class bezier_arc
{
public:
//--------------------------------------------------------------------
bezier_arc() : m_vertex(26) {}
bezier_arc(double x, double y,
double rx, double ry,
double start_angle,
double sweep_angle)
{
init(x, y, rx, ry, start_angle, sweep_angle);
}
//--------------------------------------------------------------------
void init(double x, double y,
double rx, double ry,
double start_angle,
double sweep_angle);
//--------------------------------------------------------------------
void rewind(unsigned)
{
m_vertex = 0;
}
//--------------------------------------------------------------------
unsigned vertex(double* x, double* y)
{
if(m_vertex >= m_num_vertices) return path_cmd_stop;
*x = m_vertices[m_vertex];
*y = m_vertices[m_vertex + 1];
m_vertex += 2;
return (m_vertex == 2) ? path_cmd_move_to : path_cmd_curve4;
}
// Supplemantary functions. num_vertices() actually returns doubled
// number of vertices. That is, for 1 vertex it returns 2.
//--------------------------------------------------------------------
unsigned num_vertices() const { return m_num_vertices; }
const double* vertices() const { return m_vertices; }
double* vertices() { return m_vertices; }
private:
unsigned m_vertex;
unsigned m_num_vertices;
double m_vertices[26];
};
//==========================================================bezier_arc_svg
// Compute an SVG-style bezier arc.
//
// Computes an elliptical arc from (x1, y1) to (x2, y2). The size and
// orientation of the ellipse are defined by two radii (rx, ry)
// and an x-axis-rotation, which indicates how the ellipse as a whole
// is rotated relative to the current coordinate system. The center
// (cx, cy) of the ellipse is calculated automatically to satisfy the
// constraints imposed by the other parameters.
// large-arc-flag and sweep-flag contribute to the automatic calculations
// and help determine how the arc is drawn.
class bezier_arc_svg
{
public:
//--------------------------------------------------------------------
bezier_arc_svg() : m_arc(), m_radii_ok(false) {}
bezier_arc_svg(double x1, double y1,
double rx, double ry,
double angle,
bool large_arc_flag,
bool sweep_flag,
double x2, double y2) :
m_arc(), m_radii_ok(false)
{
init(x1, y1, rx, ry, angle, large_arc_flag, sweep_flag, x2, y2);
}
//--------------------------------------------------------------------
void init(double x1, double y1,
double rx, double ry,
double angle,
bool large_arc_flag,
bool sweep_flag,
double x2, double y2);
//--------------------------------------------------------------------
bool radii_ok() const { return m_radii_ok; }
//--------------------------------------------------------------------
void rewind(unsigned)
{
m_arc.rewind(0);
}
//--------------------------------------------------------------------
unsigned vertex(double* x, double* y)
{
return m_arc.vertex(x, y);
}
// Supplemantary functions. num_vertices() actually returns doubled
// number of vertices. That is, for 1 vertex it returns 2.
//--------------------------------------------------------------------
unsigned num_vertices() const { return m_arc.num_vertices(); }
const double* vertices() const { return m_arc.vertices(); }
double* vertices() { return m_arc.vertices(); }
private:
bezier_arc m_arc;
bool m_radii_ok;
};
}
#endif
|
