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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
//----------------------------------------------------------------------------
//
// classes curve3 and curve4
//
//----------------------------------------------------------------------------
#include <math.h>
#include "agg_curves.h"
namespace agg
{
//------------------------------------------------------------------------
void curve3::init(double x1, double y1,
double x2, double y2,
double x3, double y3)
{
m_start_x = x1;
m_start_y = y1;
m_end_x = x3;
m_end_y = y3;
double dx1 = x2 - x1;
double dy1 = y2 - y1;
double dx2 = x3 - x2;
double dy2 = y3 - y2;
double len = sqrt(dx1 * dx1 + dy1 * dy1) + sqrt(dx2 * dx2 + dy2 * dy2);
m_num_steps = int(len * 0.25 * m_scale);
if(m_num_steps < 2)
{
m_num_steps = 2;
}
double subdivide_step = 1.0 / m_num_steps;
double subdivide_step2 = subdivide_step * subdivide_step;
double tmpx = (x1 - x2 * 2.0 + x3) * subdivide_step2;
double tmpy = (y1 - y2 * 2.0 + y3) * subdivide_step2;
m_saved_fx = m_fx = x1;
m_saved_fy = m_fy = y1;
m_saved_dfx = m_dfx = tmpx + (x2 - x1) * (2.0 * subdivide_step);
m_saved_dfy = m_dfy = tmpy + (y2 - y1) * (2.0 * subdivide_step);
m_ddfx = tmpx * 2.0;
m_ddfy = tmpy * 2.0;
m_step = m_num_steps;
}
//------------------------------------------------------------------------
void curve3::rewind(unsigned)
{
if(m_num_steps == 0)
{
m_step = -1;
return;
}
m_step = m_num_steps;
m_fx = m_saved_fx;
m_fy = m_saved_fy;
m_dfx = m_saved_dfx;
m_dfy = m_saved_dfy;
}
//------------------------------------------------------------------------
unsigned curve3::vertex(double* x, double* y)
{
if(m_step < 0) return path_cmd_stop;
if(m_step == m_num_steps)
{
*x = m_start_x;
*y = m_start_y;
--m_step;
return path_cmd_move_to;
}
if(m_step == 0)
{
*x = m_end_x;
*y = m_end_y;
--m_step;
return path_cmd_line_to;
}
m_fx += m_dfx;
m_fy += m_dfy;
m_dfx += m_ddfx;
m_dfy += m_ddfy;
*x = m_fx;
*y = m_fy;
--m_step;
return path_cmd_line_to;
}
//------------------------------------------------------------------------
void curve4::init(double x1, double y1,
double x2, double y2,
double x3, double y3,
double x4, double y4)
{
m_start_x = x1;
m_start_y = y1;
m_end_x = x4;
m_end_y = y4;
double dx1 = x2 - x1;
double dy1 = y2 - y1;
double dx2 = x3 - x2;
double dy2 = y3 - y2;
double dx3 = x4 - x3;
double dy3 = y4 - y3;
double len = sqrt(dx1 * dx1 + dy1 * dy1) +
sqrt(dx2 * dx2 + dy2 * dy2) +
sqrt(dx3 * dx3 + dy3 * dy3);
m_num_steps = int(len * 0.25 * m_scale);
if(m_num_steps < 2)
{
m_num_steps = 2;
}
double subdivide_step = 1.0 / m_num_steps;
double subdivide_step2 = subdivide_step * subdivide_step;
double subdivide_step3 = subdivide_step * subdivide_step * subdivide_step;
double pre1 = 3.0 * subdivide_step;
double pre2 = 3.0 * subdivide_step2;
double pre4 = 6.0 * subdivide_step2;
double pre5 = 6.0 * subdivide_step3;
double tmp1x = x1 - x2 * 2.0 + x3;
double tmp1y = y1 - y2 * 2.0 + y3;
double tmp2x = (x2 - x3) * 3.0 - x1 + x4;
double tmp2y = (y2 - y3) * 3.0 - y1 + y4;
m_saved_fx = m_fx = x1;
m_saved_fy = m_fy = y1;
m_saved_dfx = m_dfx = (x2 - x1) * pre1 + tmp1x * pre2 + tmp2x * subdivide_step3;
m_saved_dfy = m_dfy = (y2 - y1) * pre1 + tmp1y * pre2 + tmp2y * subdivide_step3;
m_saved_ddfx = m_ddfx = tmp1x * pre4 + tmp2x * pre5;
m_saved_ddfy = m_ddfy = tmp1y * pre4 + tmp2y * pre5;
m_dddfx = tmp2x * pre5;
m_dddfy = tmp2y * pre5;
m_step = m_num_steps;
}
//------------------------------------------------------------------------
void curve4::rewind(unsigned)
{
if(m_num_steps == 0)
{
m_step = -1;
return;
}
m_step = m_num_steps;
m_fx = m_saved_fx;
m_fy = m_saved_fy;
m_dfx = m_saved_dfx;
m_dfy = m_saved_dfy;
m_ddfx = m_saved_ddfx;
m_ddfy = m_saved_ddfy;
}
//------------------------------------------------------------------------
unsigned curve4::vertex(double* x, double* y)
{
if(m_step < 0) return path_cmd_stop;
if(m_step == m_num_steps)
{
*x = m_start_x;
*y = m_start_y;
--m_step;
return path_cmd_move_to;
}
if(m_step == 0)
{
*x = m_end_x;
*y = m_end_y;
--m_step;
return path_cmd_line_to;
}
m_fx += m_dfx;
m_fy += m_dfy;
m_dfx += m_ddfx;
m_dfy += m_ddfy;
m_ddfx += m_dddfx;
m_ddfy += m_dddfy;
*x = m_fx;
*y = m_fy;
--m_step;
return path_cmd_line_to;
}
}
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