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

From: Rick Byers <rbyers@chromium.org>
Date: Mon, 5 Nov 2012 11:24:01 -0500
Message-ID: <CAFUtAY__2C-+EDRYzzQ0wBuVsxFhEoAsSt0ORyeDMP+=aDjEqw@mail.gmail.com>
To: public-indie-ui <public-indie-ui@w3.org>
Cc: Robert Kroeger <rjkroege@chromium.org>
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
Received on Monday, 5 November 2012 16:24:49 GMT

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