core/vgl/vgl_clip.h File Reference

#include <vgl/vgl_box_2d.h>
#include <vgl/vgl_line_2d.h>
#include <vgl/vgl_line_segment_2d.h>
#include <vgl/vgl_polygon.h>

Go to the source code of this file.

Defines
#define	VGL_CLIP_INSTANTIATE(T)   extern "please include vgl/vgl_clip.txx instead"
Enumerations
enum	vgl_clip_type { vgl_clip_type_intersect, vgl_clip_type_union, vgl_clip_type_difference, vgl_clip_type_xor }
	Type of polygon "clip" operations. More...
Functions
template<class T >
bool	vgl_clip_lineseg_to_line (T &x1, T &y1, T &x2, T &y2, T a, T b, T c)
	clips away the portion where ax+by+c<0. return false if nothing left.
template<class T >
bool	vgl_clip_line_to_box (T a, T b, T c, T x1, T y1, T x2, T y2, T &bx, T &by, T &ex, T &ey)
	clip line ax+by+c=0 to given box. return false if no intersection.
template<class T >
vgl_line_segment_2d< T >	vgl_clip_line_to_box (vgl_line_2d< T > const &l, vgl_box_2d< T > const &b)
	clip given line to given box, and return resulting line segment.
template<class T >
vgl_polygon< T >	vgl_clip (const vgl_polygon< T > &poly1, const vgl_polygon< T > &poly2, vgl_clip_type op=vgl_clip_type_intersect)
	Clip a polygon against another polygon.
template<class T >
vgl_polygon< T >	vgl_clip (vgl_polygon< T > const &poly1, vgl_polygon< T > const &poly2, vgl_clip_type op, int *p_retval)
	Clip a polygon against another polygon.

---

Detailed Description

Author:

fsm

    Modifications
     29 Apr 2002: Amitha Perera: added a polygon clipper (a wrap around for
                                 Alan Murt's Generic Polygon Clipper)
     12 Oct 2002: Peter Vanroose: vgl_clip_line_to_box completely re-implemented
     14 Nov 2003: Peter Vanroose: made all functions templated
   

Definition in file vgl_clip.h.

---

Define Documentation

#define VGL_CLIP_INSTANTIATE

(

T

)

extern "please include vgl/vgl_clip.txx instead"

Definition at line 95 of file vgl_clip.h.

---

Enumeration Type Documentation

enum vgl_clip_type

Type of polygon "clip" operations.

Enumerator:

vgl_clip_type_intersect
vgl_clip_type_union
vgl_clip_type_difference
vgl_clip_type_xor

Definition at line 21 of file vgl_clip.h.

---

Function Documentation

template<class T >

vgl_polygon< T > vgl_clip	(	const vgl_polygon< T > &	poly1,
		const vgl_polygon< T > &	poly2,
		vgl_clip_type	op = vgl_clip_type_intersect
	)

Clip a polygon against another polygon.

The two polygons poly1 and poly2 are combined with each other. The operation (intersection, union, etc) is given by parameter op.

Note:

The implementation of this code is based on Alan Murta's GPC library (http://www.cs.man.ac.uk/aig/staff/alan/software/gpc.html) which is free for non-commercial use.

In order to be able to use it, make sure to satisfy the copyright notice, then activate the "BUILD_NONCOMMERCIAL" compiler option.

Definition at line 224 of file vgl_clip.txx.

template<class T >

vgl_polygon< T > vgl_clip	(	vgl_polygon< T > const &	poly1,
		vgl_polygon< T > const &	poly2,
		vgl_clip_type	op,
		int *	p_retval
	)

Clip a polygon against another polygon.

Same as vgl_clip( const vgl_polygon<T>& poly1, const vgl_polygon<T>& poly2, vgl_clip_type op = vgl_clip_type_intersect ); but where the fourth parameter is a return flag which is 1 if success, or 0 if the operation faced a geometric degeneracy which could not be handled. In this case, it might be necessary to perturb the input with a tiny amount of random noise and try again.

Definition at line 143 of file vgl_clip.txx.

template<class T >

bool vgl_clip_line_to_box	(	T	a,
		T	b,
		T	c,
		T	x1,
		T	y1,
		T	x2,
		T	y2,
		T &	bx,
		T &	by,
		T &	ex,
		T &	ey
	)

clip line ax+by+c=0 to given box. return false if no intersection.

Definition at line 40 of file vgl_clip.txx.

template<class T >

vgl_line_segment_2d< T > vgl_clip_line_to_box	(	vgl_line_2d< T > const &	l,
		vgl_box_2d< T > const &	b
	)		[inline]

clip given line to given box, and return resulting line segment.

Definition at line 53 of file vgl_clip.h.

template<class T >

bool vgl_clip_lineseg_to_line	(	T &	x1,
		T &	y1,
		T &	x2,
		T &	y2,
		T	a,
		T	b,
		T	c
	)

clips away the portion where ax+by+c<0. return false if nothing left.

Definition at line 14 of file vgl_clip.txx.