Author: Jonas Bilinkevicius

Is it possible to change the printer orientation from portrait to landscape in the 
middle of a print job?

Answer:
1   
2   procedure TForm1.Button2Click(Sender: TObject);
3   var
4     Device: array[0..255] of char;
5     Driver: array[0..255] of char;
6     Port: array[0..255] of char;
7     hDeviceMode: THandle;
8     pDevMode: PDeviceMode;
9   begin
10    with Printer do
11    begin
12      BeginDoc;
13      try
14        Canvas.font.size := 20;
15        Canvas.font.name := 'Arial';
16        Canvas.TextOut(50, 50, 'This is portait');
17        GetPrinter(Device, Driver, Port, hDeviceMode);
18        pDevMode := GlobalLock(hDevicemode);
19        with pDevMode^ do
20        begin
21          dmFields := dmFields or DM_ORIENTATION;
22          dmOrientation := DMORIENT_LANDSCAPE;
23        end;
24        { Cannot use NewPage here since the ResetDc will only work between EndPage
25        and StartPage. As a consequence the Printer.PageCount is not updated. }
26        Windows.EndPage(Printer.Handle);
27        if ResetDC(canvas.Handle, pDevMode^) = 0 then
28          ShowMessage('ResetDC failed, ' + SysErrorMessage(GetLastError));
29        GlobalUnlock(hDeviceMode);
30        Windows.StartPage(Printer.Handle);
31        Printer.Canvas.Refresh;
32        Canvas.font.size := 20;
33        Canvas.font.name := 'Arial';
34        Canvas.TextOut(50, 50, 'This is landscape');
35      finally
36        EndDoc;
37      end;
38    end;
39  end;