Under Win16, call the Windows API function Escape(), passing the constant GETPRINTINGOFFSET. Under Win32, simply call the Windows API function GetDeviceCaps() passing the predefined constants PHYSICALOFFSETX and PHYSICALOFFSETY. Since there is no guarantee a given escape is supported, always call Escape with the QUERYESCSUPPORT constant to make sure a given escape is implemented. The following example returns the margin of a given printer under both WIN16 and WIN32, accounting for the fact that not all printers will support the escape code GETPRINTINGOFFSET (under WIN16). If this is the case, the printing offset is approximated by getting the page size, subtracting the physical resolution of the device, and then diving by two.

uses Printers;
 
procedure TForm1.Button1Click(Sender: TObject);
var
  EscapeCode : integer;
  Margin : TPoint;
begin
  if PrintDialog1.Execute then begin
   {$IFDEF WIN32}
    Margin.x :=GetDeviceCaps(Printer.Handle, PHYSICALOFFSETX);
    Margin.y :=GetDeviceCaps(Printer.Handle, PHYSICALOFFSETY);
   {$ELSE}
    EscapeCode := GETPRINTINGOFFSET;
    if Escape(Printer.Handle,
              QUERYESCSUPPORT,
              sizeof(EscapeCode),
              @EscapeCode,
              nil) <> 0 then
      if Escape(Printer.Handle,
                GETPRINTINGOFFSET,
                0,
                nil,
                @Margin) < 1  then begin
       EscapeCode := GETPHYSPAGESIZE;
       if Escape(Printer.Handle,
                 QUERYESCSUPPORT,
                 sizeof(EscapeCode),
                 @EscapeCode,
                 nil) <> 0 then
        if Escape(Printer.Handle,
                  GETPHYSPAGESIZE,
                  0,
                  nil,
                  @Margin) > 0  then begin
          Margin.x := (Margin.x -
                       GetDeviceCaps(Printer.Handle, HorzRes)) div 2;
          Margin.y := (Margin.y -
                       GetDeviceCaps(Printer.Handle, VertRes)) div 2;
        end else begin
          Margin.x := 0;
          Margin.y := 0;
        end;
      end;
   {$ENDIF}
    Memo1.Lines.Add(IntToStr(Margin.x));
    Memo1.Lines.Add(IntToStr(Margin.y));
  end;
end;
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