When grid is very small it takes a long time to load

[Karjala22]

See if there is a way to improve the grid drawing when there are many points

[Karjala22]

Why is it recalculating M2DX(i) for each outer loop ?

procedure TMapWindow.DO_DrawGrid;
var i, j   : Integer;
    TheMsg : TMsg;
begin
  with Map.Canvas do
    begin
      i := Round(S2MX(0)/Grid)*Grid-Grid;
      while  i <= Round(S2MX(ScreenX)/Grid)*Grid+Grid do
        begin
          if FastSCROLL and
           (PeekMessage(TheMsg, 0, WM_KEYUP,   WM_KEYUP,   PM_NOYIELD or PM_NOREMOVE) or
            PeekMessage(TheMsg, 0, WM_LBUTTONDOWN, WM_LBUTTONDOWN, PM_NOYIELD or PM_NOREMOVE))
              then Break;
          j := Round(S2MZ(ScreenZ)/Grid)*Grid-Grid;
          while j <= Round(S2MZ(0)/Grid)*Grid+Grid do
            begin
              SetPixel(Handle, **M2SX(i),** M2SZ(j), col_grid);
              Inc(j ,Grid);
            end;
          Inc(i, Grid);
        end;
    end;
end;

[Karjala22]

Will rewrite to include dynamic grids drawing.