Why define NewCols in Grids.pas

[kinlion]

When using TStringGrid, I hide some columns in  the Object Inspector. Then I want to get the count of visible columns by calling StringGrid.Columns.VisibleColCount, but the result is wrong because it counts the invivible columns.
Deep into the grids.pas, I found there is a defeine at the head of the file:

Code: Pascal  [Select][+][-]

1. {$define NewCols}

and the function:

Code: Pascal  [Select][+][-]

1. function TGridColumns.GetVisibleCount: Integer;
2. {$ifNdef newcols}
3. var
4.   i: Integer;
5. {$endif}
6. begin
7.   {$ifdef newcols}
8.   result := Count;
9.   {$else}
10.   result := 0;
11.   for i:=0 to Count-1 do
12.     if Items[i].Visible then
13.       inc(result);
14.   {$endif}
15. end;
16.  

The definition makes the function igoring Coulmn's Visible property.
Why?

[kinlion]

OK. I understand it now after reading  this function:

Code: Pascal  [Select][+][-]

1. function TGridColumn.GetWidth: Integer;
2. var
3.   tmpGrid: TCustomGrid;
4. begin
5.   {$ifdef newcols}
6.   if not Visible then
7.     exit(0);
8.   {$endif}
9.   if FWidth=nil then
10.     result := GetDefaultWidth
11.   else
12.     result := FWidth^;
13.   if (result<0) then
14.   begin
15.     tmpGrid := Grid;
16.     if tmpGrid<>nil then
17.       result := tmpGrid.DefaultColWidth;
18.   end;
19. end;
20.  

To define NewCols means to treat the unvisible columns as a zero-widthed column instead of removing it from columns logically. Maybe for speeding up code.