#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))

/* canonrect:  canonicalize coordinates of rectangle */
struct rect canonrect(struct rect r)
{
	struct rect temp;

	temp.pt1.x = min(r.pt1.x, r.pt2.x);
	temp.pt1.y = min(r.pt1.y, r.pt2.y);
	temp.pt2.x = max(r.pt1.x, r.pt2.x);
	temp.pt2.y = max(r.pt1.y, r.pt2.y);
	return temp;
}