/* pixutils.h
 * RasMol2 Molecular Graphics
 * Roger Sayle, August 1995
 * Version 2.6
 */

typedef struct {
        int px, py, pz;      /* Spline Control Co-ordinate */
        int tx, ty, tz;      /* Spline Direction Vector    */
        int hnx, hny, hnz;   /* Horizontal Normal Vector   */
        int vnx, vny, vnz;   /* Vertical Normal Vector     */
        int dx, dy, dz;      /* Ribbon Height Vector       */
        int wx, wy, wz;      /* Ribbon Width Vector        */
        char hinten;         /* Horizontal Intensity       */
        char vinten;         /* Vertical Intensity         */
        short hsize;         /* Horizontal Vector Length   */
        short vsize;         /* Vertical Vector Length     */
        short wide;          /* Ribbon Width               */
    } Knot;

typedef struct {
        Pixel __huge *fbuf;
        short __huge *dbuf;
        int xmax, ymax;
        int yskip;
    } ViewStruct;

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