mapnik/deps/agg/include/agg_vcgen_smooth_poly1.h
2019-02-09 15:24:12 +00:00

271 lines
8.3 KiB
C++

//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// 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
//----------------------------------------------------------------------------
#ifndef AGG_VCGEN_SMOOTH_POLY1_INCLUDED
#define AGG_VCGEN_SMOOTH_POLY1_INCLUDED
#include "agg_basics.h"
#include "agg_vertex_sequence.h"
namespace agg
{
//======================================================vcgen_smooth
//
// Smooth polygon generator
//
//------------------------------------------------------------------------
template <class Calculate>
class vcgen_smooth
{
enum status_e
{
initial,
ready,
polygon,
ctrl_b,
ctrl_e,
ctrl1,
ctrl2,
end_poly,
stop
};
public:
typedef vertex_sequence<vertex_dist, 6> vertex_storage;
vcgen_smooth() :
m_src_vertices(),
m_smooth_value(0.5),
m_closed(0),
m_status(initial),
m_src_vertex(0) { }
vcgen_smooth(vcgen_smooth &&) = default;
void smooth_value(double v) { m_smooth_value = v * 0.5; }
double smooth_value() const { return m_smooth_value * 2.0; }
// Vertex Generator Interface
void remove_all()
{
m_src_vertices.remove_all();
m_closed = 0;
m_status = initial;
}
void add_vertex(double x, double y, unsigned cmd)
{
m_status = initial;
if(is_move_to(cmd))
{
m_src_vertices.modify_last(vertex_dist(x, y));
}
else
{
if(is_vertex(cmd))
{
m_src_vertices.add(vertex_dist(x, y));
}
else
{
m_closed = get_close_flag(cmd);
}
}
}
// Vertex Source Interface
void rewind(unsigned)
{
if(m_status == initial)
{
m_src_vertices.close(m_closed != 0);
}
m_status = ready;
m_src_vertex = 0;
}
unsigned vertex(double* x, double* y)
{
unsigned cmd = path_cmd_line_to;
while(!is_stop(cmd))
{
switch(m_status)
{
case initial:
rewind(0);
case ready:
if(m_src_vertices.size() < 2)
{
cmd = path_cmd_stop;
break;
}
if(m_src_vertices.size() == 2)
{
*x = m_src_vertices[m_src_vertex].x;
*y = m_src_vertices[m_src_vertex].y;
m_src_vertex++;
if(m_src_vertex == 1) return path_cmd_move_to;
if(m_src_vertex == 2) return path_cmd_line_to;
cmd = path_cmd_stop;
break;
}
cmd = path_cmd_move_to;
m_status = polygon;
m_src_vertex = 0;
case polygon:
if(m_closed)
{
if(m_src_vertex >= m_src_vertices.size())
{
*x = m_src_vertices[0].x;
*y = m_src_vertices[0].y;
m_status = end_poly;
return path_cmd_curve4;
}
}
else
{
if(m_src_vertex >= m_src_vertices.size() - 1)
{
*x = m_src_vertices[m_src_vertices.size() - 1].x;
*y = m_src_vertices[m_src_vertices.size() - 1].y;
m_status = end_poly;
return path_cmd_curve3;
}
}
std::tie(m_ctrl1, m_ctrl2) = Calculate::apply(
m_src_vertices.prev(m_src_vertex),
m_src_vertices.curr(m_src_vertex),
m_src_vertices.next(m_src_vertex),
m_src_vertices.next(m_src_vertex + 1),
m_smooth_value);
*x = m_src_vertices[m_src_vertex].x;
*y = m_src_vertices[m_src_vertex].y;
m_src_vertex++;
if(m_closed)
{
m_status = ctrl1;
return ((m_src_vertex == 1) ?
path_cmd_move_to :
path_cmd_curve4);
}
else
{
if(m_src_vertex == 1)
{
m_status = ctrl_b;
return path_cmd_move_to;
}
if(m_src_vertex >= m_src_vertices.size() - 1)
{
m_status = ctrl_e;
return path_cmd_curve3;
}
m_status = ctrl1;
return path_cmd_curve4;
}
break;
case ctrl_b:
*x = m_ctrl2.x;
*y = m_ctrl2.y;
m_status = polygon;
return path_cmd_curve3;
case ctrl_e:
*x = m_ctrl1.x;
*y = m_ctrl1.y;
m_status = polygon;
return path_cmd_curve3;
case ctrl1:
*x = m_ctrl1.x;
*y = m_ctrl1.y;
m_status = ctrl2;
return path_cmd_curve4;
case ctrl2:
*x = m_ctrl2.x;
*y = m_ctrl2.y;
m_status = polygon;
return path_cmd_curve4;
case end_poly:
m_status = stop;
return path_cmd_end_poly | m_closed;
case stop:
return path_cmd_stop;
}
}
return cmd;
}
private:
vcgen_smooth(const vcgen_smooth&);
const vcgen_smooth& operator = (const vcgen_smooth&);
vertex_storage m_src_vertices;
double m_smooth_value;
unsigned m_closed;
status_e m_status;
unsigned m_src_vertex;
point_d m_ctrl1;
point_d m_ctrl2;
};
struct calculate_poly1
{
using result_type = std::pair<point_d, point_d>;
static result_type apply(const vertex_dist& v0,
const vertex_dist& v1,
const vertex_dist& v2,
const vertex_dist& v3,
double smooth_value)
{
double k1 = v0.dist / (v0.dist + v1.dist);
double k2 = v1.dist / (v1.dist + v2.dist);
double xm1 = v0.x + (v2.x - v0.x) * k1;
double ym1 = v0.y + (v2.y - v0.y) * k1;
double xm2 = v1.x + (v3.x - v1.x) * k2;
double ym2 = v1.y + (v3.y - v1.y) * k2;
return {
{v1.x + smooth_value * (v2.x - xm1),
v1.y + smooth_value * (v2.y - ym1)},
{v2.x + smooth_value * (v1.x - xm2),
v2.y + smooth_value * (v1.y - ym2)}
};
}
};
using vcgen_smooth_poly1 = vcgen_smooth<calculate_poly1>;
}
#endif