[cups] Only able to print from CUPS web interface ("filter failed" error otherwise)

[Helge Blischke]

> Am 10.11.2014 um 12:18 schrieb Mario Sanchez Prada <mario at endlessm.com>:
> 
> Hi again,
> 
> On 07/11/14 18:14, Mario Sanchez Prada wrote:
>> [...]
>> I will try that on Monday (I'm leaving now), at least to know whether
>> I'm hitting the same issue or not.
>> 
> So, I've downgraded ghostscript from 9.10 back to 9.07, renamed the
> pstocanonij filter as pstocanonij-bin and wrapped it from a shell script
> like this:
> 
>    #!/bin/sh
>    export  LANG=C
>    exec /usr/lib/cups/filter/pstocanonij-bin "$@"
> 
> And that did not make a difference. However, doing a similar thing with
> the /usr/lib/cups/filter/pdftops filter (from cups-filters), did work!
> 
> I'm now reading through the code of cups and cups-filters to try to
> understand why that made such a difference (and also whether there might
> be a bug somewhere in CUPS), but I'd appreciate nevertheless if anyone
> had any insight on this in the meanwhile.
> 
> Thanks,
> Mario
> _______________________________________________

Well, knowing this, I think the issue is due to a „misused“ localized printf function (or a variant thereof),
replacing the decimal point by a decimal comma when formatting floating point numbers.
I looked into the pdftops filter source from the latest cups-filters distribution and found no 
floating point number formatting.
As this filter looks for the existence of the utility program „pdftops“ and, if found, uses this in favor of Ghostscript,
I suspect the origin of this issue is that utility, presumably from the poppler package.
To check this, you could set up your wrapper as you described for /usr/bin/pdftops (or /usr/local/bin/pdftops,depending
on where it resides) and revert your pdftops filter to the original.

If that solves the issue as well, you should file a bug for the poppler package.

Helge