Grab key scrolling

Jim Gettys jg at
Thu Apr 19 09:08:51 EDT 2007

On Thu, 2007-04-19 at 11:47 +0200, Marco Pesenti Gritti wrote:

> > 3: With the newer input code in X, you have another option.
> >     Go through the list of input devices, set the ones you want to grab
> >     to not send core events, open them, depending on usage you may want
> >     to switch the PT to rel mode, as above treat the incoming X/Y data
> >     as scrolling control.
> > 

PT  (pen/tablet) requires a relatively "sharp" point (stylus); you can't
use it with the ball of a finger pressing any reasonable amount.  And
kid's fingernails are softer than adults; I don't think use of PT is at
all feasible without a stylus.

The best we can do with the current X protocol is typified by the UI in
Google Maps, though I think we can grab the pointer relative to the root
window rather than the application window, and thereby be able to go to
the edge of the screen.  Note that you run into the edge of the touchpad
pretty quickly anyway; multiple motions by the finger are often going to
be required.
                                          - Jim

Jim Gettys
One Laptop Per Child

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