C:/Users/Malcolm/Documents/temp/binaryimagelibrary/astar.c File Reference

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "heap.h"

Data Structures
struct	APOINT

Macros
#define	FILL   0x01
#define	FILLMASK   0x01
#define	ASET   0x02
#define	BSET   0x04
#define	SETMASK   0x06
#define	NONE   0x00
#define	NORTHWEST   0x10
#define	NORTH   0x20
#define	NORTHEAST   0x30
#define	WEST   0x40
#define	EAST   0x50
#define	SOUTHWEST   0x60
#define	SOUTH   0x70
#define	SOUTHEAST   0x80
#define	LINKMASK   0xF0

Functions
int	astar (unsigned char *binary, int width, int height, int sx, int sy, int ex, int ey, int **pathx, int **pathy)

Detailed Description

A* path finding algorithm, for binary images.

It finds the path between two points by gradually expanding shells of accessible points round the two points until they meet.

Many thanks to Richard Heathfield for the heap (priority queue).

Function Documentation

int astar	(	unsigned char *	binary,
		int	width,
		int	height,
		int	sx,
		int	sy,
		int	ex,
		int	ey,
		int **	pathx,
		int **	pathy
	)

A star path finding algorithm.

Parameters

[in]	binary	- the binary image
	width	- image width
	height	- image height
	sx	- start point x-coordinate
	sy	- start point y-coordinate
	ex	- end point x coordinate
	ey	- end point y coordinate
[out]	pathx	- return for x-coordinates of path (malloced)
[out]	pathy	- return for y-coordinates of path (malloced)

Returns

Number of path points, -1 on fail.