Fwd: TouchEvents: cancelling second touchmove

Kornel - public-touchevents is the list for the Touch Events spec. 
-Regards, ArtB

-------- Original Message --------
Subject:  TouchEvents: cancelling second touchmove
Resent-Date:  Sat, 11 Jan 2014 13:22:43 +0000
Resent-From:  <www-dom@w3.org>
Date:  Sat, 11 Jan 2014 13:22:29 +0000
From:  ext Kornel Lesiński <kornel@geekhood.net>
To:  <www-dom@w3.org>



The spec says touchmove event is cancellable, but implementations have a
quirk the spec doesn't mention: only the first touchmove event can be
cancelled:

https://bugzilla.mozilla.org/show_bug.cgi?id=653009

 From a developer point of view this is a terrible misfeature I'd rather
see removed. One touchmove event is not enough to reliably detect velocity
and direction of finger movement, so it's very problematic when I want to
allow vertical page scrolling and prevent scrolling on horizontal swipe
gesture.

OTOH if it has to stay for web compatibility, then I'd rather see it
documented to warn developers against it (that behavior looks like a
bug/race condition in the code when sometimes scrolling works and
sometimes doesn't).


I've also noticed that TouchEvent.cancellable property is always true,
even in later touchmove events that effectively cannot be cancelled.
Should event.cancellable property vary per event to reflect that?

-- 
regards, Kornel

Received on Tuesday, 14 January 2014 17:55:08 UTC