/* pixutils.h
 * RasMol2 Molecular Graphics
 * Roger Sayle, October 1994
 * Version 2.5
 */

typedef struct {
        int px, py, pz;
        int wx, wy, wz;
        int tx, ty, tz;
        int cx, cy, cz;
        int inten;
	} Knot;

#define ZValid(z)     ((!UseSlabPlane) || ((z)=0)&&((x)=0)&&((y)