e_intersect.c File Reference

Vector library - intersection (lower level functions) More...

#include <stdlib.h>
#include <math.h>
#include <grass/gis.h>
#include "e_intersect.h"

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Macros
#define	SWAP(a, b)
#define	D   ((ax2 - ax1) * (by1 - by2) - (ay2 - ay1) * (bx1 - bx2))
#define	DA   ((bx1 - ax1) * (by1 - by2) - (by1 - ay1) * (bx1 - bx2))
#define	DB   ((ax2 - ax1) * (by1 - ay1) - (ay2 - ay1) * (bx1 - ax1))
#define	N   52 /* double's mantisa size in bits */

Functions
int	segment_intersection_2d_tol (double ax1, double ay1, double ax2, double ay2, double bx1, double by1, double bx2, double by2, double *x1, double *y1, double *x2, double *y2, double tol)
int	segment_intersection_2d (double ax1, double ay1, double ax2, double ay2, double bx1, double by1, double bx2, double by2, double *x1, double *y1, double *x2, double *y2)
int	almost_equal (double a, double b, int bits)

Detailed Description

Vector library - intersection (lower level functions)

Higher level functions for reading/writing/manipulating vectors.

(C) 2008-2009 by the GRASS Development Team

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author

Rewritten by Rosen Matev (Google Summer of Code 2008)

Definition in file e_intersect.c.

Macro Definition Documentation

D

#define D   ((ax2 - ax1) * (by1 - by2) - (ay2 - ay1) * (bx1 - bx2))

Definition at line 29 of file e_intersect.c.

DA

#define DA   ((bx1 - ax1) * (by1 - by2) - (by1 - ay1) * (bx1 - bx2))

Definition at line 30 of file e_intersect.c.

DB

#define DB   ((ax2 - ax1) * (by1 - ay1) - (ay2 - ay1) * (bx1 - ax1))

Definition at line 31 of file e_intersect.c.

N

#define N   52 /* double's mantisa size in bits */

Definition at line 926 of file e_intersect.c.

SWAP

#define SWAP	(		a,
			b
	)

Value:

    {                 \
        double t = a; \
        a = b;        \
        b = t;        \
    }

Definition at line 23 of file e_intersect.c.

Function Documentation

almost_equal()

int almost_equal	(	double	a,
		double	b,
		int	bits
	)

Definition at line 928 of file e_intersect.c.

segment_intersection_2d()

int segment_intersection_2d	(	double	ax1,
		double	ay1,
		double	ax2,
		double	ay2,
		double	bx1,
		double	by1,
		double	bx2,
		double	by2,
		double *	x1,
		double *	y1,
		double *	x2,
		double *	y2
	)

Definition at line 692 of file e_intersect.c.

segment_intersection_2d_tol()

int segment_intersection_2d_tol	(	double	ax1,
		double	ay1,
		double	ax2,
		double	ay2,
		double	bx1,
		double	by1,
		double	bx2,
		double	by2,
		double *	x1,
		double *	y1,
		double *	x2,
		double *	y2,
		double	tol
	)

Definition at line 361 of file e_intersect.c.