How do cups filters work

[Helge Blischke]

raith at hlrs.de wrote:
> 
> Can anybody give me a hint where I find documentation about
> how the filtering works in CUPS step by step.
> 
> I defined a Nashuatec Postscript Printer (NRGD3545) using their PPD File in CUPS. On WINDOWS I use the driver they supply. If I send the printjob from WINDOWS I get the error message printed on the NRGD3545:
> 
> ERROR: undefined
> OFFENDING COMMAND: @PJL
> 
> STACK:
> 
> I did the following testing:
> 
> 1) Printed my documment to a file on Windows and used lpr to send this file to the the NRGD3545. Perfect printout!!
> 2) Stopped the NRGD3545 printer queue on the CUPS server and print the
> same document to the CUPS server. Compare the queue file and the    Windows local file. No difference!! Use lpr to send the CUPS queue file
> directly to the printer. Ups ERROR like obove. Use lpr -oraw instead.
> Perfect printout. From CUPS error-log I can see that pstops is used to
> print the file.
> 
> the file in question looks like:
> 
> %-12345X at PJL JOB
> @PJL ENTER LANGUAGE = POSTSCRIPT
> %!PS-Adobe-3.0
> %%Title: Microsoft Word - Dokument1
> %%Creator: PScript5.dll Version 5.2.2
> %%CreationDate: 4/12/2005 15:23:43
> %%BoundingBox: (atend)
> %%DocumentNeededResources: (atend)
> %%DocumentSuppliedResources: (atend)
> %%DocumentData: Clean7Bit
> %%TargetDevice: (NRG 3545/3518/3532 PS3) (3011.103) 2
> %%LanguageLevel: 3
> %%EndComments
> 
> the first char is 0x1E = escape
> 
> If I edit the queufile and delete the first two lines. Perfect
> printout.
> 
> CUPS error-log says somewhere:
> 
> [Job 11] Page = 595x842; 12,12 to 583,830
> D [12/Apr/2005:19:31:21 +0200] [Job 11] Skipping PJL header...
> D [12/Apr/2005:19:31:21 +0200] [Job 11] slowcollate=0, slowduplex=0, sloworder=0
> D [12/Apr/2005:19:31:21 +0200] [Job 11] 0 %%Title: Microsoft Word - Dokument1^M
> 
> It seems that this is not done properly. The filter does not work
> how it is expected. As I do not know how these filters work or what
> else happens I am stuck here. I hope that more experienced users can
> help me or tell me where to find help.
> 
> regards
> 
> Dieter

The escape character should be 0x1B .
Otherewise the PJL stuff won't be recognized.

Helge

-- 
Helge Blischke
Softwareentwicklung
SRZ Berlin | Firmengruppe besscom
http://www.srz.de