[PATCH inputproto multitouch 0/9] Another round of changes

Chase Douglas chase.douglas at canonical.com
Fri Aug 5 16:14:44 PDT 2011


I have taken the latest inputproto branch and the latest multitouch
branch from Daniel and merged them. I then added these nine patches on
top. My working branch is located at:

http://cgit.freedesktop.org/~cndougla/inputproto/ multitouch

Patches 1-6 are of the simple rewrite, cleanup, clarify, simple fix
types of changes. There could be some differences of opinion about them,
but they should be fairly benign.

Patch 7 removes "Observe" grabs. The semantics of these grabs never
really fit well, and Peter believes "Raw" touch events will provide a
better solution. I don't have a good use case for this, so I won't be
developing the protocol for this.

Patch 8 removes TouchAxisClass. As I thought about it some more,
whatever per-touch valuators we provide can also be provided as pointer
valuators. I can't think of any counter-example, and it seems to
intuitively make sense to me. If so, this change will greatly simplify
the protocol and implementation and resolve any issues of pointer to
touch valuator axis mapping.

Patch 9 specifies dependent device handling when the device causes
pointer motion or button presses. Trackpads and independent devices
cause all sorts of headaches when trying to mix touch and pointer
mechanisms, but I believe the solution of canceling and resuming touches
simplifies things, allows for more use cases such as two-finger
scrolling in multiple windows, and does not limit foreseeable usecases.

I am hoping this gets us across any outstanding technical issues and
allows us to begin implementing the protocol at last :).

Thanks!

-- Chase


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