#include	"defs.h"

/*
 * Test if position lies between two others.
 *
 * p1, p2 = positions of the ends of a line segment
 * z = test position
 * return = 0 if not between, 1 if between and the segment is horizontal,
 *          2 if between and vertical
 */

INT between(p1, z, p2)
	REG DLW p1, z, p2;
{
	if((p1->y == z->y) && (p1->y == p2->y)
	    && (((p1->x <= z->x) && (z->x <= p2->x))
	    || ((p2->x <= z->x) && (z->x <= p1->x))))
		return(1);
	if((p1->x == z->x) && (p1->x == p2->x)
	    && (((p1->y <= z->y) && (z->y <= p2->y))
	    || ((p2->y <= z->y) && (z->y <= p1->y))))
		return(2);
	return(0);
}

/*
 * return point in centre of shape
 */
DL midpt(p, q)
	REG DL p, q;
{
	LOC DL1 pt;

	pt->x = (p->x + q->x) / 2;
	pt->y = (p->y + q->y) / 2;
	return(pt);
}

/*
 * Does point lie within a given box (or on edge)?
 *
 * p1, p2 = define corners of box
 * p = position to be tested
 * return = 1 -- yes; 0 -- no
 */
within(p1, p, p2)
	DL p1, p, p2;
{
	return((xydist(p1, p) + xydist(p, p2)) == xydist(p1, p2));
}

/*
 * Compute the distance between two points.
 *
 * a, b = positions
 * return = distance (delta x plus delta y)
 */
xydist(a, b)
	REG DL a, b;
{
	return(abs(a->x - b->x) + abs(a->y - b->y));
}

/*
 * test if two points are the same.
 * return(1) if so
 * return(0) if not
 */
xysame(p1,p2)
	REG DL p1, p2;
{
	if (p1->x == p2->x && p1->y == p2->y)
		return(1);
	return(0);
}