void FourToEight (ImSize, ThinMag, ThinAng)
int  ImSize;
BYTE ** ThinMag;
BYTE ** ThinAng;
{
   int   r,c, Cm, N1c,N1r, N2c,N2r, N1m,N2m;

   for (r=1; r<ImSize-1; r++) {
      for (c=1; c<ImSize-1; c++)  if (ThinMag[r][c]) {
         N1r = r-1;  N1c = c;
         N2r = r;    N2c = c+1;
         Cm  = ThinMag [r][c];
         N1m = ThinMag [N1r][N1c];
         N2m = ThinMag [N2r][N2c];
         if (Cm && N1m && N2m) {
            ThinMag [r][c] = 0;
            ThinAng [r][c] = 0;
         }else{
            N1r = r-1;  N1c = c;
            N2r = r;    N2c = c-1;
            Cm  = ThinMag [r][c];
            N1m = ThinMag [N1r][N1c];
            N2m = ThinMag [N2r][N2c];
            if (Cm && N1m && N2m) {
               ThinMag [r][c] = 0;
               ThinAng [r][c] = 0;
            }else{
               N1r = r+1;  N1c = c;
               N2r = r;    N2c = c-1;
               Cm  = ThinMag [r][c];
               N1m = ThinMag [N1r][N1c];
               N2m = ThinMag [N2r][N2c];
               if (Cm && N1m && N2m) {
                  ThinMag [r][c] = 0;
                  ThinAng [r][c] = 0;
               }else{
                  N1r = r+1;  N1c = c;
                  N2r = r;    N2c = c+1;
                  Cm  = ThinMag [r][c];
                  N1m = ThinMag [N1r][N1c];
                  N2m = ThinMag [N2r][N2c];
                  if (Cm && N1m && N2m) {
                     ThinMag [r][c] = 0;
                     ThinAng [r][c] = 0;
}  }  }  }  }  }  }
