mapnik/agg/include/agg_vpgen_clip_polyline.h
2006-01-31 23:09:52 +00:00

121 lines
3.4 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
//----------------------------------------------------------------------------
#ifndef AGG_VPGEN_CLIP_POLYLINE_INCLUDED
#define AGG_VPGEN_CLIP_POLYLINE_INCLUDED
#include "agg_basics.h"
namespace agg
{
//======================================================vpgen_clip_polyline
//
// See Implementation agg_vpgen_clip_polyline.cpp
//
class vpgen_clip_polyline
{
public:
vpgen_clip_polyline() :
m_clip_box(0, 0, 1, 1),
m_x1(0),
m_y1(0),
m_f1(0),
m_x2(0),
m_y2(0),
m_f2(0),
m_num_vertices(0),
m_vertex(0)
{
}
void clip_box(double x1, double y1, double x2, double y2)
{
m_clip_box.x1 = x1;
m_clip_box.y1 = y1;
m_clip_box.x2 = x2;
m_clip_box.y2 = y2;
m_clip_box.normalize();
}
double x1() const { return m_clip_box.x1; }
double y1() const { return m_clip_box.y1; }
double x2() const { return m_clip_box.x2; }
double y2() const { return m_clip_box.y2; }
static bool auto_close() { return false; }
static bool auto_unclose() { return true; }
void reset();
void move_to(double x, double y);
void line_to(double x, double y);
unsigned vertex(double* x, double* y);
private:
enum clipping_flags_def
{
clip_x1 = 1,
clip_x2 = 2,
clip_y1 = 4,
clip_y2 = 8
};
// Determine the clipping code of the vertex according to the
// Cyrus-Beck line clipping algorithm
//--------------------------------------------------------------------
unsigned clipping_flags_x(double x)
{
unsigned f = 0;
if(x < m_clip_box.x1) f |= clip_x1;
if(x > m_clip_box.x2) f |= clip_x2;
return f;
}
unsigned clipping_flags_y(double y)
{
unsigned f = 0;
if(y < m_clip_box.y1) f |= clip_y1;
if(y > m_clip_box.y2) f |= clip_y2;
return f;
}
unsigned clipping_flags(double x, double y)
{
return clipping_flags_x(x) | clipping_flags_y(y);
}
bool move_point(double& x, double& y, unsigned& flags);
void clip_line_segment();
private:
rect_d m_clip_box;
double m_x1;
double m_y1;
unsigned m_f1;
double m_x2;
double m_y2;
unsigned m_f2;
double m_x[2];
double m_y[2];
unsigned m_cmd[2];
unsigned m_num_vertices;
unsigned m_vertex;
};
}
#endif