Replaced VelocityTracker with a faster and more accurate
native implementation. This avoids the duplicate maintenance
overhead of having two implementations.
The new algorithm requires that the sample duration be at least
10ms in order to contribute to the velocity calculation. This
ensures that the velocity is not severely overestimated when
samples arrive in bursts.
The new algorithm computes the exponentially weighted moving
average using weights based on the relative duration of successive
sample periods.
The new algorithm is also more careful about how it handles
individual pointers going down or up and their effects on the
collected movement traces. The intent is to preserve the last
known velocity of pointers as they go up while also ensuring
that other motion samples do not count twice in that case.
Bug: 4086785
Change-Id: I2632321232c64d6b8faacdb929e33f60e64dcdd3
1. Single finger tap performs a click.
2. Single finger movement moves the pointer (hovers).
3. Button press plus movement performs click or drag.
While dragging, the pointer follows the finger that is moving
fastest. This is important if there are additional fingers
down on the touch pad for the purpose of applying force
to an integrated button underneath.
4. Two fingers near each other moving in the same direction
are coalesced as a swipe gesture under the pointer.
5. Two or more fingers moving in arbitrary directions are
transformed into touches in the vicinity of the pointer.
This makes scale/zoom and rotate gestures possible.
Added a native VelocityTracker implementation to enable intelligent
switching of the active pointer during drags.
Change-Id: I5ada57e7f2bdb9b0a791843eb354a8c706b365dc
This feature is currently used to enable dragging the start and end
selection handles of a TextView at the same time. Could be used for
other things later.
Deleted some dead code in ArrowKeyMovementMethod and CursorControllers.
Change-Id: I930accd97ca1ca1917aab8a807db2c950fc7b409
The old dispatch mechanism has been left in place and continues to
be used by default for now. To enable native input dispatch,
edit the ENABLE_NATIVE_DISPATCH constant in WindowManagerPolicy.
Includes part of the new input event NDK API. Some details TBD.
To wire up input dispatch, as the ViewRoot adds a window to the
window session it receives an InputChannel object as an output
argument. The InputChannel encapsulates the file descriptors for a
shared memory region and two pipe end-points. The ViewRoot then
provides the InputChannel to the InputQueue. Behind the
scenes, InputQueue simply attaches handlers to the native PollLoop object
that underlies the MessageQueue. This way MessageQueue doesn't need
to know anything about input dispatch per-se, it just exposes (in native
code) a PollLoop that other components can use to monitor file descriptor
state changes.
There can be zero or more targets for any given input event. Each
input target is specified by its input channel and some parameters
including flags, an X/Y coordinate offset, and the dispatch timeout.
An input target can request either synchronous dispatch (for foreground apps)
or asynchronous dispatch (fire-and-forget for wallpapers and "outside"
targets). Currently, finding the appropriate input targets for an event
requires a call back into the WindowManagerServer from native code.
In the future this will be refactored to avoid most of these callbacks
except as required to handle pending focus transitions.
End-to-end event dispatch mostly works!
To do: event injection, rate limiting, ANRs, testing, optimization, etc.
Change-Id: I8c36b2b9e0a2d27392040ecda0f51b636456de25
