[Trac #470] X's pointer acceleration is poor

Zarro Boogs per Child bugtracker at laptop.org
Fri Jan 5 00:59:11 EST 2007


#470: X's pointer acceleration is poor
-----------------------------+----------------------------------------------
 Reporter:  jg               |        Owner:  jg   
     Type:  enhancement      |       Status:  new  
 Priority:  normal           |    Milestone:  CTest
Component:  x window system  |   Resolution:       
 Keywords:                   |  
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Comment (by dhopkins):

 I added this comment to bug #369: "Incompatibilities between trackpad
 precision and the current rollover UI design", but it also applies to this
 bug.

 Consider using pie menus, which are based purely on the direction of
 motion, and exploit Fitts' law by putting each menu item target adjacent
 to the cursor, but in a different direction, with a large pie-slice shaped
 area (which extends to the screen edge). Since pie menus are based on
 direction instead of distance, and the targets are large and wedge-shaped,
 the mouse acceleration actually increases the user's control over the
 direction by quickly moving the cursor out further away from the menu
 center, giving them more "leverage" and angular precision.

 Also: Please talk to Ted Selker (selker at media.mit.edu) about all his work
 that went into developing the Trackpoint's mapping from pressure to mouse
 motion. The transfer function (pressure => cursor speed mapping curve) has
 two plateaus: one at the low end at "fine positioning" speed, and one at
 the high end just below "eye tracking" speed, so moderately quick motion
 does not move the cursor too fast for the eye to follow. Of course it has
 to be adjusted for the fine resolution of the OLPC screen, and the
 properties of the touch pad. Perhaps somebody could develop an X extension
 that implemented a smarter kind of mouse acceleration behavior, that can
 be configured with any curve. Note that IBM has patented the Trackpoint
 hardware and transfer function, so check with Ted about what's allowed, or
 if IBM will donate rights to use the patent to the OLPC project.

 Re: "This is more difficult than many naive people think." -- you can say
 that again!

-- 
Ticket URL: <http://dev.laptop.org/ticket/470#comment:1>
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