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[haiku.git] / headers / libs / agg / agg_bezier_arc.h
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1 //----------------------------------------------------------------------------
2 // Anti-Grain Geometry - Version 2.4
3 // Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
4 //
5 // Permission to copy, use, modify, sell and distribute this software
6 // is granted provided this copyright notice appears in all copies.
7 // This software is provided "as is" without express or implied
8 // warranty, and with no claim as to its suitability for any purpose.
9 //
10 //----------------------------------------------------------------------------
11 // Contact: mcseem@antigrain.com
12 // mcseemagg@yahoo.com
13 // http://www.antigrain.com
14 //----------------------------------------------------------------------------
16 // Arc generator. Produces at most 4 consecutive cubic bezier curves, i.e.,
17 // 4, 7, 10, or 13 vertices.
19 //----------------------------------------------------------------------------
21 #ifndef AGG_BEZIER_ARC_INCLUDED
22 #define AGG_BEZIER_ARC_INCLUDED
24 #include "agg_conv_transform.h"
26 namespace agg
29 //-----------------------------------------------------------------------
30 void arc_to_bezier(double cx, double cy, double rx, double ry,
31 double start_angle, double sweep_angle,
32 double* curve);
35 //==============================================================bezier_arc
36 //
37 // See implemantaion agg_bezier_arc.cpp
39 class bezier_arc
41 public:
42 //--------------------------------------------------------------------
43 bezier_arc() : m_vertex(26), m_num_vertices(0), m_cmd(path_cmd_line_to) {}
44 bezier_arc(double x, double y,
45 double rx, double ry,
46 double start_angle,
47 double sweep_angle)
49 init(x, y, rx, ry, start_angle, sweep_angle);
52 //--------------------------------------------------------------------
53 void init(double x, double y,
54 double rx, double ry,
55 double start_angle,
56 double sweep_angle);
58 //--------------------------------------------------------------------
59 void rewind(unsigned)
61 m_vertex = 0;
64 //--------------------------------------------------------------------
65 unsigned vertex(double* x, double* y)
67 if(m_vertex >= m_num_vertices) return path_cmd_stop;
68 *x = m_vertices[m_vertex];
69 *y = m_vertices[m_vertex + 1];
70 m_vertex += 2;
71 return (m_vertex == 2) ? path_cmd_move_to : m_cmd;
74 // Supplemantary functions. num_vertices() actually returns doubled
75 // number of vertices. That is, for 1 vertex it returns 2.
76 //--------------------------------------------------------------------
77 unsigned num_vertices() const { return m_num_vertices; }
78 const double* vertices() const { return m_vertices; }
79 double* vertices() { return m_vertices; }
81 private:
82 unsigned m_vertex;
83 unsigned m_num_vertices;
84 double m_vertices[26];
85 unsigned m_cmd;
90 //==========================================================bezier_arc_svg
91 // Compute an SVG-style bezier arc.
93 // Computes an elliptical arc from (x1, y1) to (x2, y2). The size and
94 // orientation of the ellipse are defined by two radii (rx, ry)
95 // and an x-axis-rotation, which indicates how the ellipse as a whole
96 // is rotated relative to the current coordinate system. The center
97 // (cx, cy) of the ellipse is calculated automatically to satisfy the
98 // constraints imposed by the other parameters.
99 // large-arc-flag and sweep-flag contribute to the automatic calculations
100 // and help determine how the arc is drawn.
101 class bezier_arc_svg
103 public:
104 //--------------------------------------------------------------------
105 bezier_arc_svg() : m_arc(), m_radii_ok(false) {}
107 bezier_arc_svg(double x1, double y1,
108 double rx, double ry,
109 double angle,
110 bool large_arc_flag,
111 bool sweep_flag,
112 double x2, double y2) :
113 m_arc(), m_radii_ok(false)
115 init(x1, y1, rx, ry, angle, large_arc_flag, sweep_flag, x2, y2);
118 //--------------------------------------------------------------------
119 void init(double x1, double y1,
120 double rx, double ry,
121 double angle,
122 bool large_arc_flag,
123 bool sweep_flag,
124 double x2, double y2);
126 //--------------------------------------------------------------------
127 bool radii_ok() const { return m_radii_ok; }
129 //--------------------------------------------------------------------
130 void rewind(unsigned)
132 m_arc.rewind(0);
135 //--------------------------------------------------------------------
136 unsigned vertex(double* x, double* y)
138 return m_arc.vertex(x, y);
141 // Supplemantary functions. num_vertices() actually returns doubled
142 // number of vertices. That is, for 1 vertex it returns 2.
143 //--------------------------------------------------------------------
144 unsigned num_vertices() const { return m_arc.num_vertices(); }
145 const double* vertices() const { return m_arc.vertices(); }
146 double* vertices() { return m_arc.vertices(); }
148 private:
149 bezier_arc m_arc;
150 bool m_radii_ok;
159 #endif