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

From: James Craig <jcraig@apple.com>
Date: Mon, 05 Nov 2012 12:21:49 -0800
Cc: public-indie-ui <public-indie-ui@w3.org>
Message-id: <C3F715A6-5DBA-45C1-8DCA-0AC6EBBE76FA@apple.com>
To: Rick Byers <rbyers@chromium.org>, Robert Kroeger <rjkroege@chromium.org>
This came up during one of the F2F meetings last week. I'd encourage you to read the minutes, but the general end result for those was to make scroll request a 2-dimensional direction and distance. Likewise a second event, panRequest, would be a variant of scrollRequest to the primary difference being that the limit values (e.g. home/end) apply to general scroll views but not on pan views.

ACTION-23: Add panRequest with pan direction (360) and distance
ACTION-27: Consider moveRequest in the context of scrollRequest and panRequest

On Nov 5, 2012, at 8:24 AM, Rick Byers <rbyers@chromium.org> wrote:

> 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 20:22:31 GMT

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