Sending esc codes to the printer (driver)

rbuser

Hello,
I use D6, RB6.03 Pro.
My reports are in Hebrew (right-to-left writing order).
In order to produce a PDF report, the best solution I found is using a
printer driver that produces a PDF file from
the print output. Using filters like Pragnaan or waller does not work, they
don't support RTL output for PDF.
The driver that does RTL PDF OK needs, in order to specify the output file
name, to send escape sequence to the printer
and I quote the tech manual: "1. The escape codes have to be sent after
PrinterDC is ready and before calling StartDoc(). (CREATEDC_POST) "

How can I do that using Report Builder. I noticed that the BeforePrint event
is triggered too early and the printer dc is built
after.
How can I do it?

TIA
Israel

digitalmetaphors

Hook into the printer device's OnStartJob. This will fire in the ancestor
TppDevice which is when the StartJob method is called, but before the
descendent TppPrinterDevice has called BeginDoc which resets the DC and
calls Delphi's StartDoc function declared in Windows.pas.

In the Report.BeforePrint event, check
if (ppReport1.PrinterDevice <> nil) then
ppReport1.PrinterDevice.OnStartJob := StartJobEvent;

As a last resort, if you have to, you can create your own TmyPrinterDevice
and register this as a new device, as it is a copy of TppPrinterDevice in
ppPrnDev.pas which has been renamed. Then you can add an event notification
where you want to in your device to be able to add escape codes when you
want to. There is a Report.PrintToDevices which can be used when you want to
control the print process manually.

Cheers,

Jim Bennett
Digital Metaphors

rbuser

Thanks Jim but...

notification
to

I tried it upto the point I realized that the BeginDoc is a procedure of
TppCustomPrinter that I cant override.
I need to trigger my custom event in the position marked with ***** in the
following code.


procedure TppCustomPrinter.BeginDoc;
var
lDocInfo: TDocInfo;
begin

if FPrinting then Exit;

FPrinting := True;
FAborted := False;
FPageNumber := 0;
FStartPage := False;

{free the current device context and call resetDC to create a new one}
FreeDC;
ResetDC;

**************************************************************
I need to triger the event/send escape codes - here
**************************************************************

FillChar(lDocInfo, SizeOf(lDocInfo), 0);
lDocInfo.cbSize := SizeOf(lDocInfo);
lDocInfo.lpszDocName := PChar(FDocumentName);

if (FFileName <> '') then
lDocInfo.lpszOutput := PChar(FFileName);

{SetAbortProc(FDC, AbortProc);}
StartDoc(FDC, lDocInfo);

end; {procedure, BeginDoc}


In addition there is a problem overriding the procedure
TppPrinterDevice.StartJob, in order to control the calling to BeginDoc
because the last line is FCanvas := Printer.Canvas and the Canvas property
is readonly so you cant do a Canvas := Printer.Canvas.

How do I go from here?

Israel

digitalmetaphors

If you have to modify the TppPrinter class, then you'll have to change your
library path to RBuilder\Source and change the source. Are you using RAP? If
so, then you won't want to change the interface section of any class, but
you'll have to in this case, because TppPrinter is not a TppCommunicator so
it can't broadcast a message to any other object. The easiest thing to do is
to add a TNotifyEvent on this class and hook into it by the
TppReport.Printer property at runtime, rather than creating an embedded
TppCommunicator. If you want to go with the more powerful communicator
approach, then take a look at the TppViewer class in ppViewr.pas, as it
creates an embedded TppCommunicator in order to communicate.


Cheers,

Jim Bennett
Digital Metaphors

rbuser

back again Jim,

rbuser

Hi,

i found this a very good feature, to insert ESC Codes before and after
Print.
With this i could handle cash-drawer to open and also to cut paper.
It might be a littlte difficult to overwrtite the printer. If possible, put
such an option to your ToDo-List for the next generation. So ESC-Codes could
be inserted easyly before and after a report (with RAP and perhaps as a
property of the Report.).

chris

digitalmetaphors

TppPrinter objects are create-embedded on different objects. I'd have to
code an example to research this feature further. Let me know in the
meantime if you get it working.


Cheers,

Jim Bennett
Digital Metaphors

rbuser

Hi Jim,
been away but this issue is still very important.