Delphi duplex printing | 易学教程

问题

I have a PVC card printer which prints on both sides of a card at the same time. take a look at this question: Delphi double-side printer

I managed to enable the duplex printing mode of the printer. now the problem is that the first page which is the front side of the card is printed fine but the back side which is the second page is printed in black and white and a very low quality. something like a monochrome bitmap.

this is the output of my program which is printed using MS XPS document printer. as you can see there is no problem here, but when I select the PVC printer, I have problems in printing the back side.

Left page is the front side of the card which is printed fine but the right page is the back side of the card and is printed in black and white and a very low quality.

var
  i, j: integer;
  ppix,ppiy,mmx,mmy: integer;
  XForm: TXForm;
  Device, Driver, Port: array[0..80] of Char;
  DevMode: THandle;
  pDevmode: PDeviceMode;
  insert_comm: wideString;
begin
  with PrintDialog1 do
if Execute then
  begin

    with printer do
      begin

        GetPrinter(Device, Driver, Port, DevMode);
        if Devmode <> 0 then begin
           // lock it to get pointer to DEVMODE record
          pDevMode := GlobalLock(Devmode);
        if pDevmode <> nil then
          try
            with pDevmode^ do begin
              dmDuplex := DMDUP_VERTICAL;
              dmFields := dmFields or DM_DUPLEX;
            end;

            BeginDoc;

            ppix:=GetDeviceCaps(Handle,LOGPIXELSX);
            ppiy:=GetDeviceCaps(Handle,LOGPIXELSY);
            mmx:=round(ppix/25.4);
            mmy:=round(ppiy/25.4);

            SetGraphicsMode(Canvas.Handle, GM_ADVANCED);
            XForm.eM11 := Cos(DegToRad(270));
            XForm.eM12 := Sin(DegToRad(270));
            XForm.eM21 := -Sin(DegToRad(270));
            XForm.eM22 := Cos(DegToRad(270));
            XForm.eDx := (PageWidth div 2) - ((54 * mmy) div 2);
            XForm.eDy := 85 * mmx;
            SetWorldTransform(Canvas.Handle, XForm);


            // Here I draw the front side of the Card


            // New page for back side
            NewPage;

            SetGraphicsMode(Canvas.Handle, GM_ADVANCED);
            XForm.eM11 := Cos(DegToRad(270));
            XForm.eM12 := -Sin(DegToRad(270));
            XForm.eM21 := Sin(DegToRad(270));
            XForm.eM22 := Cos(DegToRad(270));
            XForm.eDx := (PageHeight div 2);
            XForm.eDy := 0;
            SetWorldTransform(Canvas.Handle, XForm);


            // Here I draw the back side of the Card

            EndDoc;

            try
              bmp.Destroy;
            except
            end;


          finally
            // unlock devmode handle.
            GlobalUnlock(Devmode);
          end;
        end; { If }


      end;
end;

Thank you.

来源：https://stackoverflow.com/questions/28514198/delphi-duplex-printing

标签

Delphi

printing