[Trac #369] Incompatibilities between trackpad precision and the current rollover UI design

[Zarro Boogs per Child]

#369: Incompatibilities between trackpad precision and the current rollover UI
design
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 Reporter:  jg      |        Owner:  Eben   
     Type:  defect  |       Status:  new    
 Priority:  high    |    Milestone:  BTest-2
Component:  sugar   |   Resolution:         
 Keywords:          |  
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Changes (by Eben):

  * summary:  Getting rid of activities is unnecessarily cumbersome. =>
              Incompatibilities between trackpad precision
              and the current rollover UI design

Comment:

 Indeed, after some testing I've seen that it can be somewhat difficult to
 control.  However, the actual tracking on the pad isn't that terrible, it
 seems.  And if it's difficult to hit a 75x75 pixel square we're going to
 have much larger problems elsewhere in the interface.

 Honestly, though, I think that the bigger issue here is one of mouse
 acceleration.  If I understand it correctly (though I could be terribly
 wrong here), at the moment the mouse moves at some speed ''m,'' as does
 the cursor, up to some threshold ''k'', and above ''k'' it multiplies
 ''m'' by some acceleration factor ''a'' to yeild the new cursor speed
 ''c''. This gives us a stepwise function for its actual velocity.
 Windows, in general, operates on a linear function, where the acceleration
 factor ''a'' is directly proportional to the mouse speed ''m''.  OSX, on
 the other hand, actually defines a really nice acceleration curve with
 similar effects, but that actually seems to provide an extra degree of
 precision.

 I think we need at least a linear function, if not a nice curve, for the
 laptops.  Ideally, since the trackpad isn't of superior precision, we
 should begin with an acceleration that is less than 1 to 1.  At slow mouse
 speeds, the cursor could actually go 1/2 the speed of the mouse.  Then, as
 mouse speed increases, using a continuous function for acceleration rather
 than a threshold will prevent the mouse from jumping, which seems to be
 making it difficult to control at the moment.

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Ticket URL: <http://dev.laptop.org/ticket/369#comment:5>
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