Title: Get pixels per inch of printer
If you want to get number of pixels per inch of the current printer, then use GetDeviceCaps function.
uses Printers;
...
procedure TForm1.Button1Click(Sender: TObject);
begin
Label1.Caption:=
IntToStr(GetDeviceCaps(Printer.Handle, LogPixelsX));
Label2.caption:=
IntToStr(GetDeviceCaps(Printer.Handle, LogPixelsY));
end;