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

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 UTC