  gray_start_cell( RAS_ARG_ TCoord  ex,
                            TCoord  ey )
  {
    if ( ex > ras.max_ex )
      ex = (TCoord)( ras.max_ex );

    if ( ex < ras.min_ex )
      ex = (TCoord)( ras.min_ex - 1 );

    ras.area    = 0;
    ras.cover   = 0;
    ras.ex      = ex - ras.min_ex;
    ras.ey      = ey - ras.min_ey;
    ras.last_ey = SUBPIXELS( ey );
    ras.invalid = 0;

    gray_set_cell( RAS_VAR_ ex, ey );
  }

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.