e_intersect.c File Reference

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

Include dependency graph for e_intersect.c:

Go to the source code of this file.

Macros
#define	SWAP(a, b)   {t = a; a = b; b = t;}
#define	MIN(X, Y)   ((X<Y)?X:Y)
#define	MAX(X, Y)   ((X>Y)?X:Y)
#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)

Macro Definition Documentation

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

Definition at line 13 of file e_intersect.c.

Referenced by segment_intersection_2d().

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

Definition at line 14 of file e_intersect.c.

Referenced by segment_intersection_2d().

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

Definition at line 15 of file e_intersect.c.

Referenced by segment_intersection_2d().

#define MAX	(		X,
			Y
	)		((X>Y)?X:Y)

Definition at line 11 of file e_intersect.c.

Referenced by segment_intersection_2d(), and segment_intersection_2d_tol().

#define MIN	(		X,
			Y
	)		((X<Y)?X:Y)

Definition at line 8 of file e_intersect.c.

Referenced by segment_intersection_2d(), and segment_intersection_2d_tol().

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

Definition at line 910 of file e_intersect.c.

Referenced by almost_equal().

#define SWAP	(		a,
			b
	)		{t = a; a = b; b = t;}

Definition at line 6 of file e_intersect.c.

Referenced by segment_intersection_2d().

Function Documentation

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

Definition at line 912 of file e_intersect.c.

References N.

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 677 of file e_intersect.c.

References D, DA, DB, G_debug(), G_warning(), MAX, MIN, and SWAP.

Referenced by find_all_intersections().

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 345 of file e_intersect.c.

References FEQUAL, FZERO, G_debug(), G_warning(), MAX, and MIN.