Re: Several event types are too discrete to be useful for touchscreen input

Rick,

Can you tell us if the new Pointers working group will be addressing any
scrolling?

These events have been targeted for discreet events but if you think we are
deficient on scrolling then we should investigate the gaps and see if they
can be addressed in 1.0.

Rich


Rich Schwerdtfeger



From:	Rick Byers <rbyers@chromium.org>
To:	public-indie-ui <public-indie-ui@w3.org>,
Cc:	Robert Kroeger <rjkroege@chromium.org>
Date:	11/05/2012 10:25 AM
Subject:	Several event types are too discrete to be useful for
            touchscreen input
Sent by:	rbyers@google.com



Hi,
I know there was originally a desire that Indie UI events would be rich
enough to be useful for common touch screen interactions (eg. see
http://www.w3.org/WAI/IndieUI/wiki/Use_Cases_and_Requirements#Scenario_1:_Manipulating_a_map
).  To what extent is this still a goal?

I took a quick look at the work-in-progress spec (
https://dvcs.w3.org/hg/IndieUI/raw-file/7f84811c9874/src/events.html) and
see that a common theme is to make the events fairly discrete, eg. with an
enum of possible values.  For example, the UIScrollRequestEvent takes an
enum for one of 4 directions.  I'd love to be able to use UIScrollRequest
to, eg., pan a map with a touch screen, but for that it would need
_at_least_ some measure of distance connected to the screen (eg. scrolled
10 pixels up and 2 pixels to the right).  Even for the more common scenario
of triggering these events from a track pad, you'd need a measure of
distance.  Do you intend for UIScrollRequest to replace the use of
mousewheel (http://www.w3.org/TR/DOM-Level-3-Events/#events-WheelEvent)
events, or would apps always need to listen to both?

The overall impression I get is that these events are really designed to be
triggered by discrete operations like pressing of buttons.  I think the
approach would need to be modified (eg. to take arbitrary precision values
in place of enums) to really ever get used for any sort of continuous input
like a touch screen or track pad.  But perhaps that's no longer a goal?

Thanks,
   Rick