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;
+    }
+
+}