Smooth scrolling

Max Schwarz Max at
Mon Mar 29 05:54:09 PDT 2010


I'd like to make a proposal for mouse wheel handling.
Today's pointer devices often have the capability to get more
resolution on the mouse wheel velocity than the old click-by-click wheels.
For example, for an IBM TrackPoint user the EmulateWheel option is very nice,
but it's very disconcerting to see the screen move 3 lines at a time
instead of one smooth motion. Same behaviour with mouse wheel
emulation on touchpads.
I know that there are attempts to correct this on the client side (i.e. 
Firefox smooth-scrolling) but because of the missing resolution in Xinput 
events the clickety-feel remains.

I'm ready to put considerate effort into this issue, I just need someone with 
experience to tell me where to start.

I see two ways of improving the resolution:

1) Just send more axis up/down button events
This would break compability. Old software just expecting a few button "ticks" 
would suddenly scroll wildly.

2) Provide additional axis events with true resolution

I realize that the GUI frameworks would also need work to make them use the 
new interface.

Thank you,
  Max Schwarz

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