diff options
Diffstat (limited to 'agg/source/agg_arc.cpp')
-rwxr-xr-x | agg/source/agg_arc.cpp | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/agg/source/agg_arc.cpp b/agg/source/agg_arc.cpp new file mode 100755 index 000000000000..eb10f5f7f2fc --- /dev/null +++ b/agg/source/agg_arc.cpp @@ -0,0 +1,105 @@ +//---------------------------------------------------------------------------- +// 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 +//---------------------------------------------------------------------------- +// +// 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_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) + { + m_da = fabs(1.0 / ((m_rx + m_ry) * 0.5 * m_scale)); + 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; + } + +} |