Smooth scrolling

[Max Schwarz]

Hi Simon,

> The problem I see is that it's really degrees or cycles on a wheel, or
> some distance on more freaky devices (e.g. pad on mouse). Maybe it's
> preferable to add some (user-overrideable) axis information which
> toolkits may use to ultimately do something sensible.

Well the way it is now the driver maintainers decide how often they sent the 
scroll button presses. I thought I would keep it that way and let them decide 
how many pixels to scroll. Of course the user would have to be able to change 
that setting.
Anything else would create problems in interpretation later on. For example, 
equal distances on small and huge touchpads could mean very different amounts 
of pixels to scroll.
In addition to that, users should be able to change the amount of scrolling on 
a per-device basis, so the conversion should be made in driver-space in my 
opinion.

> Now for my suggestion: when things work fine (i.e. not now ;), you may
> want to add acceleration to the scroll wheel. The ptrveloc.h header
> contains the necessary methods to create an 'acceleration context', feed
> it with the wheel data and map it over acceleration functions. I think
> some windows drivers implement such a feature.

Thank you very much for the suggestion. I had thought of acceleration before, 
but as you said, I first have to get basic event reporting working.
ptrveloc.h is a very good hint though, X.org is really a place to get lost in 
:-)

Max