[cairo] postscript genarated by 1.5.20 blocks Dell5100cn

[Jiri Cerny]

Hi Carl,

thank you for the answer. I opened bug 15455 in cairo bugzilla for
this problem.
I attached there two files, one good one and one bad one.

These two files differ in approx 400 lines/100 character. Do you have
some idea what can create the difference.

Jiri


On Thu, Apr 10, 2008 at 7:45 PM, Carl Worth <cworth at cworth.org> wrote:
> On Thu, 10 Apr 2008 18:55:52 +0200, "Jiri Cerny" wrote:
>  > I recently updated to rawhide with new cairo 1.5.20. Now, when I try
>  > to print a pdf file it simply blocks our Dell5100cn printer for more
>  > than 60 minutes (may be more, I switched off the printer after this
>  > time. It is not possible to cancel the job).  It happens with at least
>  > 3 different PDF's so it does not seem to be file dependent.
>
>  Hi Jiri,
>
>  Thank you very much for reporting this bug.
>
>  It may not be file-dependent, but we could definitely use your help
>  debugging this problem, (particularly since none of us have direct
>  access to such a printer that I know of).
>
>  So one thing that would be helpful first of all is if you could
>  generate the smallest possible PostScript file that causes a problem
>  with your printer. Then if you can send that to us, we can start
>  debugging further.
>
>
>  > I did some bisecting and what I get is following:
>  ...
>
> >     Make PS backend use cairo-pdf-operators.c
>
>  Thanks for bisecting down to that.
>
>  What this commit does is define some, (very small), PostScript
>  functions at the beginning of the PostScript output. These PostScript
>  functions are then called later in the file for creating paths,
>  stroking, and positioning glyphs.
>
>  We designed these functions so that they are named identically to (and
>  act compatibly with) operators within the PDF specification. This
>  allows the PostScript and PDF backends within cairo to emit identical
>  output for large portions output-file, (reducing code and bug
>  duplication within cairo).
>
>
>  > The postscripts files that are generated during the bisecting are
>  > always viewable by gv (Some of them have some moved glyphs), so there
>  > is probably some bad interaction with the printer.
>  >
>  > It might be related to bug 15348 ?
>
>  Yes, in both cases it's likely that there are printer bugs in dealing
>  with the PostScript file, (and it's also possible that cairo's
>  PostScript output is in error). And as discussed in that bug report,
>  we're going to need more information on exactly what it is that the
>  printer doesn't like. So once we have a minimal file, (as can be
>  produced by cairo), that causes problems with the printer, the next
>  step would be to trim that file down further by hand until the problem
>  is as isolated as possible.
>
>  Then the problem can be reported to the vendor of the printer, and we
>  can also see what we can do to workaround the problem in cairo.
>
>
>  > I can post the files and do some other testing, but better tomorow.
>
>  Yes, please, as described above.
>
>  Thanks so much for your report,
>
>  -Carl
>