I use Okular almost daily for studying course material. The annotations work really well with a touchscreen. If I double-click an annotation tool with the mouse it "freezes", which effectively gives me the ability to draw over pdfs like they were printed papers. 

However there are tiny but really important "tweaks" that can make Okular much more touch-screen friendly.


1. Annotation tools can be selected by the keyboard shortcuts [1, 2, 3, ...]. However double pressing any of those keys doesn't freeze the annotation.

2. Double tapping an annotation tool through the touchscreen doesn't freeze it.

3. Adding a popup note, then typing in the note sometimes causes the pdf to scroll for no apparent reason.

4. Inline note causes the pdf to scroll while typing in order to observe the changes on the pdf itself. I do the pdf positioning myself so I wish I can disable that feature.

5. Many times the pdf is rotated unintentionally while panning. I wish I can at least disable the rotation effect or control it's sensitivity. I would rarely need to rotate the pdf with my hands, and even if I do, I would reach out for the menu bar.



The above features are the very most important. They first two would allow the user to control the type of the annotation with one hand (on the keyboard) and draw or pan with the other. Here's more touchscreen wishes below.

6. Pinching the screen to zoom is a bit jittery.

7. Sliding a finger to pan creates no momentum (or acceleration). Meaning, once finger is released, panning stops.



My favorite pdf editor! Thanks for all the beautiful work :D

SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version: 5.14
KDE Frameworks 5.50.0
Qt 5.11.1 (built against 5.11.1)