GNOME Bugzilla – Bug 320567
evince needs lookahead and lookbehind caching
Last modified: 2018-05-22 13:06:27 UTC
Distribution/Version: Ubuntu Breezy Although the temporary white page (bug 320352) is the greatest inconvence, it is another inconvent to load pages too slow. Imagine a page renders in > 0.5 seconds during a presentation. It is already annoying to move to the next page a bit slow (imagine bug 320352 is fixed - press the button and nothing changed until 0.5 seconds later it suddenly goes to the new page). Skipping 3 pages at a time is pretty much unacceptablely slow. I think evince should cache (at least) a couple of (say 5) pages before and after the current page, so that they can be reached nearly instanteously. It doesn't seem necessary to "forget" the cached pages, since during presentation time, I probably only need evince to work - I won't care other applications being swapped out of RAM due to evince requiring more RAM.
Hello! Now that you tell everyone should use evince to replace ggv and gpdf, but you ignore major bugs that make it unusable, for 6 months.
Well, it could be done, someone should just handle this problem and write a patch. But probably just faster rendering will help more.
So another 6 months. For the past year, I can only either use gpdf (compile from source of course, which distro still comes with it?) or adobe reader (non-free!) for presentation. Perhaps I should try kpdf? Faster rendering can solve a lot of problems. But it is not easy to do either. Caching is a easier and more sensible approach. During presentation, one stops in the slide for at least a few seconds. Why not take this time to render? In the Q&A session, perhaps you need to go back 20 pages to illustrate a point. At present, going back these 20 pages takes way too much time! A typical presentation have at most around a hundred slides. Each slide takes the screen size, i.e. a few megabyte (uncompressed). A typical computer is capable of caching at least a fraction of the slides, if not all. This is the reason there is a "presentation mode" - it should be optimized for presentation, during which the computer does nothing else. Of course this feature maybe useful for normal use, but caching should be less aggressive.
And in normal mode it should be conscious of the current free memory on the computer, to prevent thrashing.
Bug #342110 is somewhat related, to keep thumbnails in memory. Usability-wise, either thumbnails or the actual pages need to be possible to quickly flip through, that's the issue.
-- GitLab Migration Automatic Message -- This bug has been migrated to GNOME's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.gnome.org/GNOME/evince/issues/18.