107 lines
3.1 KiB
C++
107 lines
3.1 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
|
||
|
|
//----------------------------------------------------------------------------
|
||
|
|
//
|
||
|
|
// Arc vertex generator
|
||
|
|
//
|
||
|
|
//----------------------------------------------------------------------------
|
||
|
|
|
||
|
|
#include <math.h>
|
||
|
|
#include "agg_arc.h"
|
||
|
|
|
||
|
|
|
||
|
|
namespace agg
|
||
|
|
{
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
arc::arc(double x, double y,
|
||
|
|
double rx, double ry,
|
||
|
|
double a1, double a2,
|
||
|
|
bool ccw) :
|
||
|
|
m_x(x), m_y(y), m_rx(rx), m_ry(ry), m_scale(1.0)
|
||
|
|
{
|
||
|
|
normalize(a1, a2, ccw);
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
void arc::init(double x, double y,
|
||
|
|
double rx, double ry,
|
||
|
|
double a1, double a2,
|
||
|
|
bool ccw)
|
||
|
|
{
|
||
|
|
m_x = x; m_y = y;
|
||
|
|
m_rx = rx; m_ry = ry;
|
||
|
|
normalize(a1, a2, ccw);
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
void arc::approximation_scale(double s)
|
||
|
|
{
|
||
|
|
m_scale = s;
|
||
|
|
if(m_initialized)
|
||
|
|
{
|
||
|
|
normalize(m_start, m_end, m_ccw);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
void arc::rewind(unsigned)
|
||
|
|
{
|
||
|
|
m_path_cmd = path_cmd_move_to;
|
||
|
|
m_angle = m_start;
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
unsigned arc::vertex(double* x, double* y)
|
||
|
|
{
|
||
|
|
if(is_stop(m_path_cmd)) return path_cmd_stop;
|
||
|
|
if((m_angle < m_end - m_da/4) != m_ccw)
|
||
|
|
{
|
||
|
|
*x = m_x + cos(m_end) * m_rx;
|
||
|
|
*y = m_y + sin(m_end) * m_ry;
|
||
|
|
m_path_cmd = path_cmd_stop;
|
||
|
|
return path_cmd_line_to;
|
||
|
|
}
|
||
|
|
|
||
|
|
*x = m_x + cos(m_angle) * m_rx;
|
||
|
|
*y = m_y + sin(m_angle) * m_ry;
|
||
|
|
|
||
|
|
m_angle += m_da;
|
||
|
|
|
||
|
|
unsigned pf = m_path_cmd;
|
||
|
|
m_path_cmd = path_cmd_line_to;
|
||
|
|
return pf;
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------
|
||
|
|
void arc::normalize(double a1, double a2, bool ccw)
|
||
|
|
{
|
||
|
|
double ra = (fabs(m_rx) + fabs(m_ry)) / 2;
|
||
|
|
m_da = acos(ra / (ra + 0.125 / m_scale)) * 2;
|
||
|
|
if(ccw)
|
||
|
|
{
|
||
|
|
while(a2 < a1) a2 += pi * 2.0;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
while(a1 < a2) a1 += pi * 2.0;
|
||
|
|
m_da = -m_da;
|
||
|
|
}
|
||
|
|
m_ccw = ccw;
|
||
|
|
m_start = a1;
|
||
|
|
m_end = a2;
|
||
|
|
m_initialized = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|