When slowly scrolling through a yet uncached pdf the content of the next page is rendered (or displayed) with a significant delay. I've recorded a video to better illustrate the problem https://streamable.com/ynpjz System settings: Screen Scale set to 2 Okular settings: View mode: Single page, Continuous; Memory usage: Greedy Some additional observations: - noticeable only on a hidpi screen - better noticeable when the okular window is more wide; barely noticeable when the window is tall; not noticeable when the View mode is set to Facing Pages; - happens on every Memory Usage setting
Thanks for the report. I guess a similar file would be this one?: https://sourceforge.net/projects/manjarolinux/files/archive/17.0.1/Manjaro-17.0.1-User-Guide.pdf Also, could you let us know your version of the Poppler library, please? (Okular provides different rendering related features depending on the level of support in that library.)
poppler version: 0.61.1-1 The exact file doesn't really matter I guess, but yes the file you linked would be nearly identical.
Hmh, cannot reproduce. I tried exactly the versions of Okular and Poppler as well as the settings you mentioned, but there is absolutely no difference at all between HiDPI and normal scaling, and even on my slow machine I don't have such a huge delay. +1 for showing the system load applet in your video, this way we see you are not running out of RAM, so that's not the culprit. I tried on a FullHD screen, but your screen resolution would be interesting to know as well (looks like 4K?). Also, how do you scroll exactly? Keyboard, mouse, touchpad?
Yes it's a 3840x2160 15" display; it happens with every input device I tried: keyboard, trackpoint, touchpad.
Thanks, I guess we'd need someone with such a high resolution display to try to reproduce. There's one more thing you could try: Does this also happen when you use the same screen, but set scaling to 1x? This way we would know whether this is more about the screen dimensions/pixmap size, or the special HiDPI rendering mode.
I've tested and it works properly with scaling set to 1.
I have, I think, the same problem on my new computer (Dell XPS 13, Fedora 30, okular 18.12.2, poppler 0.73.0) The computer has a resolution 3840x2160 and Screen Scale is set at 2.5. Like Eugene, I notice that it mostly happen with large windows. Okular even seems to give up at some points and doesn't render parts of the page till I move again. I have also put a file on (this is the file pgfmanual.pdf in package texlive-pgf-doc) look how rendering is flickering and how page 7 doesn't appear till I go up and down again. The computer is brand new, everything is going very smoothly with evince, so I don't think the problem is a lack of CPU or RAM. It works much better with Screen Scale set at 1.