160 lines
5.6 KiB
C
160 lines
5.6 KiB
C
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//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.4
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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//----------------------------------------------------------------------------
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
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//
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// Arc generator. Produces at most 4 consecutive cubic bezier curves, i.e.,
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// 4, 7, 10, or 13 vertices.
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//
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//----------------------------------------------------------------------------
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#ifndef AGG_BEZIER_ARC_INCLUDED
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#define AGG_BEZIER_ARC_INCLUDED
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#include "agg_conv_transform.h"
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namespace agg
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{
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//-----------------------------------------------------------------------
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void arc_to_bezier(double cx, double cy, double rx, double ry,
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double start_angle, double sweep_angle,
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double* curve);
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//==============================================================bezier_arc
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//
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// See implemantaion agg_bezier_arc.cpp
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//
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class bezier_arc
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{
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public:
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//--------------------------------------------------------------------
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bezier_arc() : m_vertex(26), m_num_vertices(0), m_cmd(path_cmd_line_to) {}
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bezier_arc(double x, double y,
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double rx, double ry,
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double start_angle,
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double sweep_angle)
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{
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init(x, y, rx, ry, start_angle, sweep_angle);
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}
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//--------------------------------------------------------------------
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void init(double x, double y,
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double rx, double ry,
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double start_angle,
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double sweep_angle);
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//--------------------------------------------------------------------
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void rewind(unsigned)
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{
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m_vertex = 0;
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}
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//--------------------------------------------------------------------
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unsigned vertex(double* x, double* y)
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{
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if(m_vertex >= m_num_vertices) return path_cmd_stop;
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*x = m_vertices[m_vertex];
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*y = m_vertices[m_vertex + 1];
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m_vertex += 2;
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return (m_vertex == 2) ? unsigned(path_cmd_move_to) : m_cmd;
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}
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// Supplemantary functions. num_vertices() actually returns doubled
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// number of vertices. That is, for 1 vertex it returns 2.
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//--------------------------------------------------------------------
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unsigned num_vertices() const { return m_num_vertices; }
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const double* vertices() const { return m_vertices; }
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double* vertices() { return m_vertices; }
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private:
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unsigned m_vertex;
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unsigned m_num_vertices;
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double m_vertices[26];
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unsigned m_cmd;
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};
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//==========================================================bezier_arc_svg
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// Compute an SVG-style bezier arc.
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//
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// Computes an elliptical arc from (x1, y1) to (x2, y2). The size and
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// orientation of the ellipse are defined by two radii (rx, ry)
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// and an x-axis-rotation, which indicates how the ellipse as a whole
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// is rotated relative to the current coordinate system. The center
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// (cx, cy) of the ellipse is calculated automatically to satisfy the
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// constraints imposed by the other parameters.
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// large-arc-flag and sweep-flag contribute to the automatic calculations
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// and help determine how the arc is drawn.
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class bezier_arc_svg
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{
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public:
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//--------------------------------------------------------------------
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bezier_arc_svg() : m_arc(), m_radii_ok(false) {}
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bezier_arc_svg(double x1, double y1,
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double rx, double ry,
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double angle,
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bool large_arc_flag,
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bool sweep_flag,
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double x2, double y2) :
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m_arc(), m_radii_ok(false)
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{
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init(x1, y1, rx, ry, angle, large_arc_flag, sweep_flag, x2, y2);
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}
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//--------------------------------------------------------------------
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void init(double x1, double y1,
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double rx, double ry,
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double angle,
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bool large_arc_flag,
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bool sweep_flag,
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double x2, double y2);
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//--------------------------------------------------------------------
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bool radii_ok() const { return m_radii_ok; }
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//--------------------------------------------------------------------
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void rewind(unsigned)
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{
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m_arc.rewind(0);
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}
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//--------------------------------------------------------------------
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unsigned vertex(double* x, double* y)
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{
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return m_arc.vertex(x, y);
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}
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// Supplemantary functions. num_vertices() actually returns doubled
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// number of vertices. That is, for 1 vertex it returns 2.
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//--------------------------------------------------------------------
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unsigned num_vertices() const { return m_arc.num_vertices(); }
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const double* vertices() const { return m_arc.vertices(); }
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double* vertices() { return m_arc.vertices(); }
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private:
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bezier_arc m_arc;
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bool m_radii_ok;
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};
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}
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#endif
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