学步园

procedure TSDIAppForm.Button2Click(Sender: TObject);
var
   pxprint,pyprint:Integer;
   rect:Trect;
   jpg: TJPEGImage;
begin
  inherited;
  try
    //获得打印机的分辨率,就是每英寸多少个像素
    pxprint := getdevicecaps(printer.Handle,logpixelsx);
    pyprint := getdevicecaps(printer.Handle,logpixelsy);
    //设置图片的打印区域，现在用的是A4：21cm*29.5cm
      with  rect  do
        begin
            left  := 0;
            top   := 0;
            right := trunc(21*0.3937008*pxprint);
            bottom:= trunc(29.5*0.3937008*pyprint);
        end;
    //向打印机输出图片
    jpg := TJPEGImage.Create;
    jpg.LoadFromFile('.\jpgtemp\frompro-000.jpg');
     with   jpg {image1.Picture.Bitmap}   do
        begin
            printer.Title:= '图片打印 ';
            try
                printer.begindoc;
                printer.canvas.StretchDraw(rect,jpg);
                application.ProcessMessages;
                printer.enddoc;
            except
                printer.Abort;
                raise;
            end;
        end;
  except
      showmessage( '没有打印机，请选择打印机！ ');
  end;
  jpg.free;
end;

开始时别忘了“uses jpeg;”