void NeighInds (ImSize, Dir, r,c, r0,c0,r1,c1)
int ImSize, Dir, r,c, *r0,*c0,*r1,*c1;
{
   if (80<=Dir && Dir<112) {
      *r0 = r-1;   *c0 = c+1;  /* NO-SW */
      *r1 = r+1;   *c1 = c-1;
   }else if (48<=Dir && Dir<80) {
      *r0 = r-1;   *c0 = c;    /* N-S */
      *r1 = r+1;   *c1 = c;
   }else if (16<=Dir && Dir<48) {
      *r0 = r-1;   *c0 = c-1;  /* NW-SO */
      *r1 = r+1;   *c1 = c+1;
   }else{
      *r0 = r;   *c0 = c+1;    /* O-W */
      *r1 = r;   *c1 = c-1;
   }
   if (*r0>=ImSize)  *r0 = ImSize-1;   if (*r0<0)  *r0 = 0;
   if (*c0>=ImSize)  *c0 = ImSize-1;   if (*c0<0)  *c0 = 0;
   if (*r1>=ImSize)  *r1 = ImSize-1;   if (*r1<0)  *r1 = 0;
   if (*c1>=ImSize)  *c1 = ImSize-1;   if (*c1<0)  *c1 = 0;
}
