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-rwxr-xr-xagg/source/agg_vpgen_clip_polygon.cpp133
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diff --git a/agg/source/agg_vpgen_clip_polygon.cpp b/agg/source/agg_vpgen_clip_polygon.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 "agg_vpgen_clip_polygon.h"
+#include "agg_clip_liang_barsky.h"
+
+namespace agg
+{
+
+ //------------------------------------------------------------------------
+ // Determine the clipping code of the vertex according to the
+ // Cyrus-Beck line clipping algorithm
+ //
+ // | |
+ // 0110 | 0010 | 0011
+ // | |
+ // -------+--------+-------- clip_box.y2
+ // | |
+ // 0100 | 0000 | 0001
+ // | |
+ // -------+--------+-------- clip_box.y1
+ // | |
+ // 1100 | 1000 | 1001
+ // | |
+ // clip_box.x1 clip_box.x2
+ //
+ //
+ unsigned vpgen_clip_polygon::clipping_flags(double x, double y)
+ {
+ if(x < m_clip_box.x1)
+ {
+ if(y > m_clip_box.y2) return 6;
+ if(y < m_clip_box.y1) return 12;
+ return 4;
+ }
+
+ if(x > m_clip_box.x2)
+ {
+ if(y > m_clip_box.y2) return 3;
+ if(y < m_clip_box.y1) return 9;
+ return 1;
+ }
+
+ if(y > m_clip_box.y2) return 2;
+ if(y < m_clip_box.y1) return 8;
+
+ return 0;
+ }
+
+ //----------------------------------------------------------------------------
+ void vpgen_clip_polygon::reset()
+ {
+ m_vertex = 0;
+ m_num_vertices = 0;
+ }
+
+ //----------------------------------------------------------------------------
+ void vpgen_clip_polygon::move_to(double x, double y)
+ {
+ m_vertex = 0;
+ m_num_vertices = 0;
+ m_clip_flags = clipping_flags(x, y);
+ if(m_clip_flags == 0)
+ {
+ m_x[0] = x;
+ m_y[0] = y;
+ m_num_vertices = 1;
+ }
+ m_x1 = x;
+ m_y1 = y;
+ m_cmd = path_cmd_move_to;
+ }
+
+
+ //----------------------------------------------------------------------------
+ void vpgen_clip_polygon::line_to(double x, double y)
+ {
+ m_vertex = 0;
+ m_num_vertices = 0;
+ unsigned flags = clipping_flags(x, y);
+
+ if(m_clip_flags == flags)
+ {
+ if(flags == 0)
+ {
+ m_x[0] = x;
+ m_y[0] = y;
+ m_num_vertices = 1;
+ }
+ }
+ else
+ {
+ m_num_vertices = clip_liang_barsky(m_x1, m_y1,
+ x, y,
+ m_clip_box,
+ m_x, m_y);
+ }
+
+ m_clip_flags = flags;
+ m_x1 = x;
+ m_y1 = y;
+ }
+
+
+ //----------------------------------------------------------------------------
+ unsigned vpgen_clip_polygon::vertex(double* x, double* y)
+ {
+ if(m_vertex < m_num_vertices)
+ {
+ *x = m_x[m_vertex];
+ *y = m_y[m_vertex];
+ ++m_vertex;
+ unsigned cmd = m_cmd;
+ m_cmd = path_cmd_line_to;
+ return cmd;
+ }
+ return path_cmd_stop;
+ }
+
+
+}