Marking low because ghostscript is probably too slow for this sort of things.

OTOH, according to http://lwn.net/Articles/113094/ kghostview has thumbnails.

If there's no practical way of showing bookmarks, the sidebar should perhaps be
hidden for postscript files, and the option to show it disabled (this would also
make sense for other non-thumbnailable formats, like most image formats, etc).

If this is impossible for usability reasons (the user would not understand why
the sidebar appears in some cases and doesn't in others) maybe setting the
sidebar in a disabled, un-clickable state ?

Hiding it would be confusing for the person.  Leaving it there but disabled is
probably the best option in terms of the "action of least surprise" usability
rule.  Bug 164811 talks about the index being disabled or hidden when there is
not index available. 

I'm thinking we should just go with insensitive/disabled in the view when those
elements are not available.

I'm note totally convinced hiding the sidebar would be confusing.

Given the way evince works (no preferences, keep the interface to a minimum,
etc) people should not even be aware that they use evince, they should just
think of it as viewing a document. In that way, it seems reasonable to base the
application features on what is available in the document, instead of trying to
impose features (ie thumbnails) on a document that do not support them.

Because they don't know it's the same app that opens a PDF (with thumbnails) and
a postscript (without thumbnails), they should not be surprised by the absence
of the sidebar when there's no need for one. However, as they don't know it's
the same app, they will be surprised to find a useless sidebar when opening a
document with no need for one.

I'm not sure I'm really clear here :-)

Ok, I think the confusing part here is that we also are thinking about this
notion of remembering application/document settings WRT the sidebar and other
elements.  Like in bug 163570 and bug 164772

This is about deciding if we want evince to remember settings on some level
(application or document based) or if we want to to auto-determine settings each
time.  But we probably can't have all of these settings systems working at the
same time or else we run into confusing situations.

I'm a bit confused about this. Can it be considered a dup of bug 164811 ? (Just
for a different sidebar item). Is the behavior described there what we want?

How about showing page numbers, showing a fragment of text?  (e.g. the middle
words on a page)  Or sniffing the titles based on font information?  Or running
OTS on the page's textual content?

Oh, I think I was getting confused on the fact that postscript documents don't
ever offer an index at all so if there are no thumbnails then there is nothing
for us to show.  This makes sense to do.  

jrb had shown using the Index space to just show page numbers, but I'm dubious
of the usefulness of that element.  The person already knows the number pages
available from the toolbar as well as what page they are on.  Displaying just
page numbers one by one in a list doesn't sound all that helpful.  Maybe it is...

So I'd say this is a dup of bug 164811 from the opposite angle, not sure if you
wan to mark it as a dup or treat it differently.

We should give this a try now that we have threads. To have acceptable perf we
should avoid to restart gs every time we render to a pixmap of different size.

*** Bug 321080 has been marked as a duplicate of this bug. ***

*** Bug 326439 has been marked as a duplicate of this bug. ***

Ubuntu bug about that: https://launchpad.net/distros/ubuntu/+source/evince/+bug/35357

Fixed, we have now thumbnails for PS documents too.