[webkit-dev] assumption about point packing in multit-touch tests

Tomeu Vizoso tomeu at tomeuvizoso.net
Wed Jul 18 08:59:31 PDT 2012


I'm working in adding support for the Touch Events W3C API to the
Clutter port (and plan to do the same for the Gtk+ one afterwards) and
I'm finding a problem when running the tests because they assume that
the underlying platform allows packing touch point updates within
single touch events.

Clutter (and Gtk+, for that matter) provide thin APIs on top of
XInput's which does no packing at all: each touch point update is a
touch event.

Tests such as basic-multi-touch-events-limited.js assume that the
platform is able to emit touch events that contain more than one touch
point update and also that WebCore will get the same grouping of touch
points, but that's not true in XInput-based platforms.

Though the W3C spec allows packing more than one touch point update in
a single touch event, it says nothing about how these updates should
be packed, so I think that the current tests are too restrictive and
should be relaxed to stop assuming anything about how the updates are
packed into events.

I would change the tests to check that after generating a series of
touch point updates, the web page has received each of those touch
point updates, but not check anything about how they were packed in
touch events. Does it make sense to everybody?



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