Version: (using KDE KDE 4.0.0) Installed from: Compiled From Sources Scrolling performance worsens noticeably when text is selected. Steps to reproduce: 1. Open a PDF document containing a mixture of text and pictures. 2. Scroll up and down with the mousewheel. Scrolling feels smooth and quick. 3. Select the Text Selection tool from the menu and select a few words on a page. 4. Scroll up and down with the mousewheel. Scrolling feels choppy whether or not the selected text is currently visible in the viewport.
THe text selection is painted by okular itself, the backend is not involved in that. We try to do our best in that, but of course the painting gets slower than w/o selection. (Although, I did remember it was not painful.)
With Qt's paint debugging feature enabled (export QT_FLUSH_PAINT=1) you can see that when selecting text, Okular repaints the entire viewport whenever the selection is changed. When scrolling without a text selection, only the newly exposed content in the viewport is drawn. When scrolling with a text selection, the entire viewport is repainted every time the content is moved.
The problem seems related to the information widget (the small popup on the top right (or left for RTL languages) corner of the page view). When you are in modes when that widget is shown persistently, or until you click it, (eg the zoom and the selection modes), then we get repaints for all the viewport, even if just scrolling with no rect/text selection and even if by just 1 pixel.
Can you confirm clicking (thus hiding) the information widget making the scrolling fast again?
> Can you confirm clicking (thus hiding) the information widget making the scrolling fast again? Yes. Turning off the hint/information option in Okular's settings also works as well.
Whenever I use the filte or the search feature and results become highlighted, scrolling is extremely slow. I down't have the problem with the info-message. Turning it on or of, doesn't make any difference. Srolling through a search result is unusable.
Scrolling is slow also when using certain annotation features such as highlighting. As soon as the highlighting is no longer visible, scrolling becomes normal (fast) again. This is in KDE 4.4.
I am experiencing this too when i use the search feature. Scrolling is slow only when i am on the page that contains the highlighted search text.
This bug has been quiet in a while, and I can't reproduce it with 0.12.2. Is this still an issue for the original commiter? If not, we can close the bug.
Now in kde 4.6.4, I no longer experience this issue.
I propose to close as FIXED then.