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agg_vpgen_clip_polyline.cpp
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agg_vpgen_clip_polyline.cpp
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//----------------------------------------------------------------------------
// 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
//----------------------------------------------------------------------------
#include <math.h>
#include "agg_vpgen_clip_polyline.h"
namespace agg
{
static double clip_epsilon = 1e-10;
//----------------------------------------------------------------------------
void vpgen_clip_polyline::reset()
{
m_vertex = 0;
m_num_vertices = 0;
}
//----------------------------------------------------------------------------
void vpgen_clip_polyline::move_to(double x, double y)
{
m_vertex = 0;
m_num_vertices = 0;
m_f1 = clipping_flags(x, y);
if(m_f1 == 0)
{
m_x[0] = x;
m_y[0] = y;
m_cmd[0] = path_cmd_move_to;
m_num_vertices = 1;
}
m_x1 = x;
m_y1 = y;
}
//----------------------------------------------------------------------------
bool vpgen_clip_polyline::move_point(double& x, double& y, unsigned& flags)
{
double bound;
if(flags & (clip_x1 | clip_x2))
{
bound = (flags & clip_x1) ? m_clip_box.x1 : m_clip_box.x2;
y = (bound - m_x1) * (m_y2 - m_y1) / (m_x2 - m_x1) + m_y1;
x = bound;
flags = clipping_flags_y(y);
}
if(fabs(m_y2 - m_y1) < clip_epsilon && fabs(m_x2 - m_x1) < clip_epsilon)
{
return false;
}
if(flags & (clip_y1 | clip_y2))
{
bound = (flags & clip_y1) ? m_clip_box.y1 : m_clip_box.y2;
x = (bound - m_y1) * (m_x2 - m_x1) / (m_y2 - m_y1) + m_x1;
y = bound;
}
flags = 0;
return true;
}
//----------------------------------------------------------------------------
void vpgen_clip_polyline::clip_line_segment()
{
if((m_f1 & m_f2) == 0)
{
if(m_f1)
{
if(!move_point(m_x1, m_y1, m_f1)) return;
if(m_f1) return;
m_x[0] = m_x1;
m_y[0] = m_y1;
m_cmd[0] = path_cmd_move_to;
m_num_vertices = 1;
}
if(m_f2)
{ // Move Point 2
if(!move_point(m_x2, m_y2, m_f2)) return;
}
m_x[m_num_vertices] = m_x2;
m_y[m_num_vertices] = m_y2;
m_cmd[m_num_vertices++] = path_cmd_line_to;
}
}
//----------------------------------------------------------------------------
void vpgen_clip_polyline::line_to(double x, double y)
{
m_vertex = 0;
m_num_vertices = 0;
unsigned f = m_f2 = clipping_flags(m_x2 = x, m_y2 = y);
if(m_f2 == m_f1)
{
if(m_f2 == 0)
{
m_x[0] = x;
m_y[0] = y;
m_cmd[0] = path_cmd_line_to;
m_num_vertices = 1;
}
}
else
{
clip_line_segment();
}
m_f1 = f;
m_x1 = x;
m_y1 = y;
}
//----------------------------------------------------------------------------
unsigned vpgen_clip_polyline::vertex(double* x, double* y)
{
if(m_vertex < m_num_vertices)
{
*x = m_x[m_vertex];
*y = m_y[m_vertex];
return m_cmd[m_vertex++];
}
return path_cmd_stop;
}
}