[rdesktop-devel] Ideas on printer-redirect

[<Pan...@in...>]

Dear All,

        I have some ideas on printer-redirect.

        

        Several days ago, I tried to realize the printer-redirect with Rdesktop-5.0 and Rdesktop-6.0 for one of our department’s projects. That project was an absolute linux-based embedded system, with Arm926-ejs, 128MB DDR and some other peripheral equipments. And my printer is Epson Stylus C63 with USB interface.

        

        At first, I saw some instructions on the web and it said that the following changes should be done in embedded system

1.     add kernel support

2.     porting CUPS

3.     porting Guten-print

4.     start Rdesktop with “-r printer:mydesktop=“EPSON Stylus C63”” to enter server driver.

 

The key source code is in “printer.c”, from line 113 to line 121, it seems that the Rdesktop mount the printer to server as a network-printer, and use the “lpr” command to deal with the received flow from server. The procedure is shown as below

 

(File  ->  Driver)  -->-->  Network Printer -->-->   (CUPS -> Driver -> Dev Node) -->-->  Printer

(Windows Server)                                                   (Linux Client)

 

I tried but found it was almostly impossible for an embedded system, it takes a lot of flash-space and CPU resource.

And then I aborted porting the Guten-print but trying to find a new way. And fortunately, one day our Windows engineer told me that the flow which has been worked by Windows’s driver could directly transfer to printer.

 

For example, I do the following changes in source code “printer.c”

1.     comment (or delete )from line 113 to 121:

#if 0

if (pprinter_data->printer == "mydeskjet")

{

pprinter_data->printer_fp = popen("lpr", "w");

}

else

{

sprintf(cmd, "lpr -P %s", pprinter_data->printer);

pprinter_data->printer_fp = popen(cmd, "w");

}

#endif 

2. add : 

pprinter_data->printer_fp = fopen("/dev/usb/lp0", "w");

 

Then start rdesktop and use parameter “-r printer:mydesktop=“EPSON Stylus C63”” to enter server driver, it was OK and working very well !!

So, the procedure now is

       

        (File -> Driver)  -->-->  Network Printer -->-->   (Dev Node) -->-->  Printer

           (Windows Server)                                         (Linux Client)

 

With this change, we do not need to porting any local printer-service component but could support any printer supported by Server-Windows.

I hope this discovery could be helpful for our community.

 

 

Thanks & Regards

Pan David

Embedded Sys&App SW Dept.

IPT R&D Center, Inventec (PuDong) Corp.

789 Puxing Road, Min Hang District, Shanghai 201114, China

Tel: 86-21-6429-8888 Ext: 62851