Delphi papersize at printer device

http://mc-computing.com/languages/delphi/Printing.html

http://www.massmind.org/Techref/language/delphi/swag/DELPHI0091.html

http://www.delphigroups.info/2/b5/135338.html

https://stackoverflow.com/questions/3864060/printer-print-size

https://groups.google.com/forum/#!topic/borland.public.delphi.ide/XoxgHS96yv4

http://box.cs.istu.ru/public/docs/other/_New/Books/Lang/Delphi/Delphi%20Developer's%20Guide/Ebooks/d5dg/chapter10.pdf

https://community.embarcadero.com/article/technical-articles/162-programming/12185-changing-the-papersize-of-a-print-job

https://www.tek-tips.com/viewthread.cfm?qid=193081

procedure SetPrinterSettings(FPrinter: TPrinter);
var
  FDevice: PChar;
  FDriver: PChar;
  FPort: PChar;
  DeviceMode: THandle;
  DevMode: PDeviceMode;
begin
  {to get a current printer settings}
  FPrinter.GetPrinter(FDevice, FDriver, FPort, DeviceMode);
  {lock a printer device}
  DevMode := GlobalLock(DeviceMode);

  {set a paper size as A4-Transverse}
  if ((DevMode^.dmFields and DM_PAPERSIZE) = DM_PAPERSIZE) then
  begin
    DevMode^.dmFields := DevMode^.dmFields or DM_PAPERSIZE;
    DevMode^.dmPaperSize := DMPAPER_A4_TRANSVERSE;
  end;

  {set a paper source as Tractor bin}
  if  ((DevMode^.dmFields and DM_DEFAULTSOURCE) = DM_DEFAULTSOURCE) then
  begin
    DevMode^.dmFields := DevMode^.dmFields or DM_DEFAULTSOURCE;
    DevMode^.dmDefaultSource := DMBIN_TRACTOR;
  end;

  {set a Landscape orientation}
  if  ((DevMode^.dmFields and DM_ORIENTATION) = DM_ORIENTATION) then
  begin
    DevMode^.dmFields := DevMode^.dmFields or DM_ORIENTATION;
    DevMode^.dmOrientation := DMORIENT_LANDSCAPE;
  end;

  {set a printer settings}
  FPrinter.SetPrinter(FDevice, FDriver, FPort, DeviceMode);

  {unlock a device}
  GlobalUnlock(DeviceMode);
end;

//-----------------------------------

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;
PDMode : PDEVMODE;
begin
  Printer.PrinterIndex := Printer.PrinterIndex;
  Printer.GetPrinter(Device, Driver, Port, hDMode);
  if hDMode <> 0 then begin
    pDMode := GlobalLock(hDMode);
    if pDMode <> nil then begin

     {Set to legal}
      pDMode^.dmFields := pDMode^.dmFields or dm_PaperSize;
      pDMode^.dmPaperSize := DMPAPER_LEGAL;

     {Set to custom size}
      pDMode^.dmFields := pDMode^.dmFields or 
                          DM_PAPERSIZE or
                          DM_PAPERWIDTH or
                          DM_PAPERLENGTH;
      pDMode^.dmPaperSize := DMPAPER_USER;
      pDMode^.dmPaperWidth := 100 {SomeValueInTenthsOfAMillimeter};
      pDMode^.dmPaperLength := 100 {SomeValueInTenthsOfAMillimeter};

     {Set the bin to use}
      pDMode^.dmFields := pDMode^.dmFields or DMBIN_MANUAL;
      pDMode^.dmDefaultSource := DMBIN_MANUAL;

      GlobalUnlock(hDMode);
    end;
  end;
  Printer.PrinterIndex := Printer.PrinterIndex;
  Printer.BeginDoc;
  Printer.Canvas.TextOut(100,100, 'Test 1');
  Printer.EndDoc;
end;

//----------------------------



I want to print data on a pre-printed paper. it's length is 4.25". so I coded like this

Printer.GetPrinter(Adevice,Adriver,Aport,DeviceHandle);
PixelsInInchX:=GetDeviceCaps(Printer.Handle,LOGPIXELSX);
PixelsInInchY:=GetDeviceCaps(Printer.Handle, LOGPIXELSY);
DevMode:=globallock(DeviceHandle);
with DevMode^ do
begin
dmFields := DM_PAPERSIZE or DM_DEFAULTSOURCE or
DM_PAPERWIDTH or DM_PAPERLENGTH;
dmpapersize:=DMPAPER_USER;
dmPaperWidth :=(PixelsInInchX*8.5);
dmPaperLength:=(PixelsInInchY*4.25); //}1101;
end;
printer.SetPrinter(Adevice,Adriver,Aport,DeviceHandle);

But when I run the program the paper length is 612(dmpaperLength returns 612). So I just try to put values and I got my paper size when I put dmPaperLength with 1100 or 1101. The big problem is I want the value between these two values as 1100.5, but I can't put that value because dmPaperLength is an integer type.
It is a pre-printed paper so I must have that size and I want to use that paper in dotmatrix printer.after I print in one page if I don't give my length as correct value the next page data will not be in proper place.

Any body have any idea??