Version: (using Devel) OS: Linux Installed from: Compiled sources Note: this wish includes a proposal to scratch-my-own-itch if you'll just tell me where to start. A useful "cheat" to give the user a great speed impression, is that as soon as he has changed the zoom level, you display an instant preview by just fast-scaling the existing image (the currently displayed page). This doesn't take any significant time and has a surprising effect on the user experience. The user is willing to forgive the poor quality of the preview because he knows it's temporary and he doesn't have time to look at it carefully anyway. That is also useful as it allows to know right away where the text will appear (useful at high zoom level). I implemented that in the Mandelbrot wallpaper plugin, as you can check. The code (very generic actually) is there: http://websvn.kde.org/trunk/KDE/kdeplasma-addons/wallpapers/mandelbrot/mandelbrot.cpp?view=markup See the zoomView() method. If you want, and if you can show me where and how I plug that into Okular, I volunteer to implement that.
I posted points 2) and 3) as issues #209630 and #209632.
We already do that (reuse old pixmap until new one arrives), if it's not happening it's either a) a bug b) the old pixmap got kicked by the memory cache algorithm Feel free to investigate further
*** Bug 209630 has been marked as a duplicate of this bug. ***
I'm a bit puzzled that you say that you're already doing that. If that's the case, then when I click "zoom in" I should see an instant preview. But in practice, especially at high zoom levels, there can be 1 second between the time when i release the mouse button and the first appearance of any results. Either I'm hitting a bug, or we're not talking about the same thing at all.
Ah wait, you say "We already do that (reuse old pixmap until new one arrives)", that I don't question at all. What I'm proposing here is a bit different: not only reuse, but _scale_ the old pixmap (huh. perhaps it'd be more efficient if that was an image instead of a pixmap).
> not only reuse, but _scale_ the old pixmap Done already since ages.
(In reply to comment #6) > > not only reuse, but _scale_ the old pixmap > > Done already since ages. I can actually see this (I was formerly incorrectly assuming that it was a new low-res rendering). BUT it is not happening instantly. When I press "Zoom In" and release, the preview certainly doesn't appear instantly. I'll try to have a look at the code! I'm pretty sure that this is a bug.
OK, Indeed you did this "instant previews" already! But the problem is that they are not actually "instant" because there's this big latency before the slotZoomIn() is even called, see this other new bug: https://bugs.kde.org/show_bug.cgi?id=209680 Anyway, closing this one as invalid.