rmacmaster abandoned this revision.
rmacmaster added a comment.
Sorry, I sort of abandoned this patch because I got caught up in other things.
* Smooth scrolling: Scrolling using the scroll wheel, arrow keys,
PageUp/PageDown keys, or the spacebar will results in an animated transition
effect rather than the view "jumping" to the new location
* Pixel scrolling: Doing a two-finger scroll gesture on a touchpad scrolls
scroll pixel-by pixel proportionally with your fingers' movement, rather than
the movement being interpreted as a scroll wheel and advancing the view by a
fixed or user-configurable number of lines
Originally, I was going for the first implementation, where users have the
option to enable / disable the animation.
I was inspired by the Mozilla Firefox UI, which allows users to toggle
"smooth scrolling" in their preferences with a checkbox option.
Smooth scrolling seems to be a controversial feature. Some people love it,
but others really hate it and don't understand why others love it.
I'm one of those people who's addicted to his phone, so I've grown spoiled by
mobile scrolling.
On a phone, you can hold your finger on the screen and drag the text
line-by-line smoothly.
Okular's instant scrolling is a little hard on my eyes when I read text at
different zoom levels.
Sometimes I need to hit the arrow key multiple times to feed a single line of
text.
Sometimes one keystroke is too little, but two keystrokes is too much.
The patch I wrote is basic and filled with bugs.
It does two things poorly (controlling step size and animating the scroll).
This could possibly be solved by experimenting with the timers built into
Okular, but a better approach is probably more along the lines of what you
mentioned.
I think the responsibility of enabling smooth scrolling should fall on the Qt
widgets rather than the Okular scroll event processing functions.
Qt has a QScrollBar widget. Perhaps a QSmoothScrollBar or an instance method
with a boolean option to enable smooth scrolling could be added.
I'm running KDE on Debian, so I don't have a system setting I can change to
universally enable smooth scrolling like those on Ubuntu might.
- Step Size
Changing the step size might be a nice feature to add on its own.
It's simple and can be added as a configuration parameter with a default
value of 20.
This would allow users to fiddle with the step size so that it works
comfortably at their desired zoom level.
A step size of 20 may work well for 100% zoom, but what about 150%, 80%, full
screen?
Here are some links showing demand for a smooth scrolling feature:
http://okular-devel.kde.narkive.com/ZM0xtQx4/okular-bug-319870-new-add-smooth-scrolling
https://askubuntu.com/questions/66489/is-there-a-way-to-enable-smooth-scrolling-for-pdfs
REPOSITORY
R223 Okular
REVISION DETAIL
https://phabricator.kde.org/D9857
To: rmacmaster, okular-devel, #okular, ngraham
Cc: ngraham, #okular, michaelweghorn, simgunz, aacid
