[delphi-en] Delphi printing problem

pri_sama Thu, 21 Apr 2005 04:12:50 -0700


We are encountering a Delphi printing problem when we try to use a 
modified DevMode.


When we save and reset the DevMode, the Printer.setPrinter method 
sends only a few hundred bytes to the printer.

What we did were,
1. Call Printer Properties Dialog. Do some changes with Printer 
Property dialog. 
2. Save the modified DevMode in PrnLst (TStringList) as a object.
3. Reset the Saved DevMode again to the selected printer when press 
the  PrintOK button.

We used the following source code to implement this:

///////////////////////////////////////////////////////////
Private
PrnLst : TStrings;


procedure TFrmPrnDld.ButtonPropertiesClick(Sender: TObject);
var
  ADevice, ADriver, APort: array[0..MAX_PATH] of Char;
  hDevMode :THandle;
  ADevMode :PDeviceMode;
  hDevModeOrg :THandle;
begin
   Printer().GetPrinter(ADevice, ADriver, APort, hDevModeOrg);
   hDevMode := copyGlobal(hDevModeOrg);
   ADevMode := GlobalLock(hDevMode);

   //Copies
   ADevMode^.dmCopies  := Trunc(SpinEdCollate.Editor.value);

  try
    if (DocumentProperties(Self.Handle, 0, ADevice, ADevMode^, 
ADevMode^,
        DM_IN_BUFFER or DM_IN_PROMPT or DM_OUT_BUFFER) <> IDOK) then 
exit;

    storeDevMode(PrinterCombo.ItemIndex, ADevMode, GlobalSize
(hDevMode));
  finally
    GlobalUnlock(hDevMode);
    GlobalFree(hDevMode);
  end;
end;

procedure TFrmPrnDld.okButClick(Sender: TObject);
begin
  getPrinter(PrinterCombo.ItemIndex);
  ModalResult := mrOk;
end;

procedure TFrmPrnDld.storeDevMode(PrinterIndex :integer; 
ADevMode :PDeviceMode; ADevSize :integer);
var
   hTemp :THandle;
   pdmTemp :PDeviceMode;
begin
   if (PrinterIndex = -1) then exit;

   if (THandle(PrnLst.Objects[PrinterIndex]) <> 0) then begin
     hTemp := THandle(PrnLst.Objects[PrinterIndex]);
     GlobalFree(hTemp);
   end;

   hTemp := GlobalAlloc(GHND, ADevSize);
   pdmTemp := GlobalLock(hTemp);
   try
      System.Move(ADevMode^, pdmTemp^, ADevSize);
   finally
      GlobalUnlock(hTemp);
   end;

   PrnLst.Objects[PrinterIndex] := TObject(hTemp);
end;

function TFrmPrnDld.getPrinter(PrinterIndex :integer) :boolean;
var
   hTemp :THandle;
begin
   Result := false;
   if (PrinterIndex = -1) then exit;

   Printer().PrinterIndex := PrinterIndex;
   Printer().GetPrinter(ADevice, ADriver, APort, ADeviceMode);

   //Get previous printer setting
   hTemp := 0;

   if (PrnLst.Objects[PrinterIndex] <> nil) then begin
      hTemp := copyGlobal(THandle(PrnLst.Objects[PrinterIndex]));
   end;

   //Some printers may fail the above GetPrinter
   Printer().SetPrinter(ADevice, ADriver, APort, hTemp);
   Printer().GetPrinter(ADevice, ADriver, APort, ADeviceMode);

   Result := true;
end;

function TFrmPrnDld.copyGlobal(hSource :HGLOBAL) :HGLOBAL;
var
   intSize :integer;
   pSrc, pDest :PByte;
begin
   Result := 0;
   if (hSource = 0) then exit;

   pSrc := GlobalLock(hSource);
   try
      intSize := GlobalSize(hSource);
      Result := GlobalAlloc(GHND, intSize);
      pDest := GlobalLock(Result);
      try
         System.Move(pSrc^, pDest^, intSize);
      finally
         GlobalUnlock(Result);
      end;
   finally
      GlobalUnlock(hSource);
   end;
end;


///////////////////////////////////////////////////////////////////

This problem can be seen only for certain types of printers such 
as "Cannon LBP 740".

Did any one encountered a similar problem? Please help.
(Delphi 5)

Thank you,
pri_sama.





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[delphi-en] Delphi printing problem

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