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Re: Hover click with pointer events

From: Patrick H. Lauke <redux@splintered.co.uk>
Date: Tue, 16 Jun 2015 17:14:14 +0100
To: public-pointer-events@w3.org
Message-ID: <55804B56.9070807@splintered.co.uk>
On 16/06/2015 17:02, Mustaq Ahmed wrote:
>  From a different perspective, the PE spec has events only for
> change-of-state with respect to the touch surface (pointerup,
> pointermove, ...), and we piggyback button-change states to those
> events. I think to support the hover-button-changes, we /need/ a
> separate event, like "buttonchange" or "hoverchange". The "buttonchange"
> event would also make sense for a touching pen that is not moving.

Note that pointerover, pointermove and pointerout fire (and are per 
spec, or rather the spec does not explicitly mention that they need to 
be only for pen contact) for hovering pointers (on Surface 3 anyway). So 
I don't think the "respect to the touch surface" part is accurate.

Scott pointed out (on IRC) that the spec also currently states that a 
button state change is meant to fire a pointermove - see 

"Additionally, when a pointer changes button state, pressure, tilt, or 
contact geometry (e.g. width and height) and the circumstances produce 
no other pointer events defined in this specification then a user agent 
must fire a pointer event named pointermove."

> For Patrick's Question (b), tracking "pointerup" and "pointerdown"
> should be enough to differentiate between a pen's hovering vs touching
> states, right? Then a "buttonchange" could represent the "click" in
> either state. I am assuming you meant by "click" a button-press, not a
> "surface-touched" event.

When mentioning "click", I just picked up on the OT talking about "Hover 
Click" interactions...but more generally, I was also thinking about 
being able to easily differentiate between a pointermove that is 
happening for a hovered stylus vs a stylus that has pen contact on the 

Sure, manually keeping track of pointerup/pointerdown is easily done, 
but wondered if there's any mileage in simply exposing a property (which 
would greatly reduce the need for devs to track event flows). To me, 
whether a stylus is touching or not touching the surface is simply 
another property akin to its orientation, position, pressure, etc, so 
philosophically it would make sense to me to have it as a property. 

Or should a hovering stylus have a specific pressure? (not tested, 
perhaps this is already the case in Surface 3...a pressure of 0 perhaps? 
or -1 to make absolutely sure it's not simply lightly resting on the 
touch surface?)

Patrick H. Lauke

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Received on Tuesday, 16 June 2015 16:14:38 UTC

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