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;
///////////////////////////////////////////////////////////////
获得边缘坐标
var
  pntMargins : TPoint;
begin
  Escape(Printer.Handle, GETPRINTINGOFFSET,0,nil,@prntMargins);
end;

Getting the Right and Bottom Margins aren't quite so straightforward. There isn't an equivalent Escape call. You obtain these values by getting the physical width (physWidth) and height (physHeight) of the page, the printable width (PrintWidth) and height (PrintHeight) of the page, and then carrying out the following sums:

RightMargin    := physWidth  - PrintWidth  - LeftMargin
BottomMargin := physHeight - PrintHeight - TopMargin
The physical page size is found using Escape, this time with the GETPHYSPAGESIZE parameter. The point pntPageSize contains the page width in pntPageSize.x and page height in pntPageSize.y

var
  pntPageSize : TPoint;
begin
   Escape(Printer.Handle,     GETPHYSPAGESIZE,o,nil,@pntPageSize);
end;