Detecting what direction a printer will rotate for a portrait

Question:

Some printers seems to rotate the portrait orientation to achieve a landscape page differently than others. This seems to affect the direction of a rotated font. How can I tell what direction a printer will rotate output on a landscape page, and if landscape mode is available on a given printer?

Answer:

The following example demonstrates how to call the Windows API function DeviceCapabilities(), to find out how a portrait page is rotated to achieve a landscape page, enabling you to adjust your output accordingly. Generally, a print driver will rotate a landscape page either 90 degrees, or 270 degrees from its portrait orientation.

Example:

uses Printers;

{$IFDEF WIN32}

function DeviceCapabilitiesA(pDevice : PAnsiChar;

pPort : PAnsiChar;

fwCapability : Word;

pOutput : PAnsiChar;

DevMode : PDeviceModeA): Integer stdcall;

external 'winspool.drv' name 'DeviceCapabilitiesA';

function DeviceCapabilitiesW(pDevice : PWideChar;

pPort : PWideChar;

fwCapability: Word;

pOutput: PWideChar;

DevMode: PDeviceModeW): Integer stdcall;

external 'winspool.drv' name 'DeviceCapabilitiesW';

function DeviceCapabilities(pDevice : PChar;

pPort : PChar;

fwCapability : Word;

pOutput : PChar;

DevMode: PDeviceMode): Integer stdcall

external 'winspool.drv' name 'DeviceCapabilitiesA';

{$ENDIF}

procedure TForm1.Button1Click(Sender: TObject);

var

Device : array[0..255] of char;

Driver : array[0..255] of char;

Port : array[0..255] of char;

hDMode : THandle;

Rotation : integer;

begin

if PrintDialog1.Execute then begin

{Reset the printer}

Printer.PrinterIndex := Printer.PrinterIndex;

Printer.GetPrinter(Device, Driver, Port, hDMode);

Rotation :=

DeviceCapabilities(Device,

Port,

DC_ORIENTATION,

nil,

nil);

case Rotation of

0 : ShowMessage('This device does not ' +

'support landscape');

90 : ShowMessage('This device rotates the portrait ' +

'orientation 90 degrees ' +

'to support landscape');

270 : ShowMessage('This device rotates the portrait ' +

'orientation 270 degrees ' +

'to support landscape');

end;