anchor.diff:        end
         else if S[I] in [bssRidge, bssGroove] then
         begin {ridge or groove}
  -        Color := C[I] or PalRelative;
           Bnd[0] := PO[I];
           Bnd[1] := PO[(I + 1) mod 4];
           Bnd[2] := PM[(I + 1) mod 4];
  
positive.code:   function Lighter(Color: TColor): TColor;
    {find a somewhat lighter color for shading purposes}
    const
      CF = 1.15; // CF > 1 makes color lighter
      CP = trunc(255 / CF);
    var
      Red, Green, Blue, Lightest: Byte;
      F: single;
    begin
      if Color and $80000000 = $80000000 then
        Color := GetSysColor(Color and $FFFFFF)
  
negative.code:       Red := Color and $FF;
        Green := (Color and $FF00) shr 8;
        Blue := (Color and $FF0000) shr 16;
        Result := RGB(Min(255, Round(F * Red)), Min(255, Round(F * Green)), Min(255, Round(F * Blue)));
      end;
    end;
  