Re: Questions RE: Hit Regions before return to Last Call

On Tue, Apr 8, 2014 at 4:03 PM, Mark Sadecki <mark@w3.org> wrote:

> On 4/8/14, 3:38 PM, Rik Cabanier wrote:
> > Hi Mark,
> >
> > thanks for sending this out!
> > However, the issue of event retargeting is still not solved. Since this
> is so
> > complex to implement, it is be unlikely that we will have 2 independent
> > implementations soon and that we won't have to make additional changes
> to the spec.
> Hi Rik,
>
> I think we agreed that the canvas element would receive all of the mouse
> events
> http://www.w3.org/2014/03/31-1-html-a11y-minutes.html#item05 (see the
> resolution)
>
> Can you outline the additional challenges we still need to solve?
>

The section that starts with "When a MouseEvent is to be fired at a canvas
element by the user agent in response to a pointing device action" needs to
be rewritten.
Also, it would be great if we could get feedback on this from browser
vendor.

>
> >
> > On Tue, Apr 8, 2014 at 2:55 PM, Mark Sadecki <mark@w3.org <mailto:
> mark@w3.org>>
> > wrote:
> >
> >     As we prepare to move Canvas back to LC (we have committed to get
> the HTML WG
> >     chairs a stable document *this* week), I reviewed the Hit Regions
> section of
> >     Canvas L1 ED [1] and had the following questions:
> >
> >     # if control is null
> >
> >     Should we have a step in "The region representing the control" [2]
> processing
> >     algorithm that matches Step 1 in "The region representing the ID"
> [3] that reads
> >     something like:
> >
> >     "If control is null, return nothing and abort these steps."
> >
> >     Now that control and ID are both optional, I think we should handle
> the case
> >     that they are not specified.
> >
> >
> > Yes, we've been going back and forth on that.
> > Since we now have the 'clearHitRegions' call and it was allowed in the
> original
> > proposal, let's allow unbacked regions with no ID.
> >
> >
> >
> >     # clearHitRegions() not defined
> >
> >     While we reference clearHitRegions() in a Note following "The region
> for a
> >     pixel" algorithm [4], we don't define a processing algorithm for
> this method.
> >     Suggest adding one below the removeHitRegion() definition [5].
> >
> >     # Move Note RE: clearRect() and clearHitRegions()
> >
> >     The note referenced above [4] would make more sense following the
> definition of
> >     removeHitRegion() and clearHitRegions() where we actually discuss
> methods for
> >     removing and/or clearing Hit Regions.
> >
> >     # Steps 5 & 8 from addHitRegion() [6] are unclear and seem to
> suggest the
> >     opposite of their intention.
> >
> >     Steps 5 & 8, as they are worded, seem to suggest to me that if the
> ID or control
> >     referenced in the arguments object are not null, and they reference
> the ID or
> >     control of a previous region, then the *previous* region should
> remain
> >     associated with this region.  This is in direct conflict with steps
> 9 & 10 and
> >     the behavior we discussed on call, that adding a Hit Region that
> shares a
> >     control or ID with a previously referenced region would remove/clear
> the
> >     previous region.
> >
> >     I also feel like steps 5 & 8 should both come before or after step
> 7, not before
> >     and after it.  There may be a reason for this order that I'm not
> aware of,
> >     though.
> >
> >
> > It is worded a bit strange but the "previous region for the id/control"
> is an
> > object that is used in steps 9 and 10.
> >
> >
> >
> >     I look forward to your feedback,
> >
> >     Mark
> >
> >     [1]
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#hit-regions
> >     [2]
> >
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#the-region-representing-the-control
> >     [3]
> >
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#the-region-identified-by-the-id
> >     [4]
> >
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#the-region-for-a-pixel
> >     [5]
> >
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#dom-context-2d-removehitregion
> >     [6]
> >
> http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#dom-context-2d-addhitregion
> >     --
> >     Mark Sadecki
> >     Web Accessibility Engineer
> >     World Wide Web Consortium, Web Accessibility Initiative
> >     Telephone: +1.617.715.4017 <tel:%2B1.617.715.4017>
> >     Email: mark@w3.org <mailto:mark@w3.org>
> >     Web: http://w3.org/People/mark
> >
> >
>
>
> --
> Mark Sadecki
> Web Accessibility Engineer
> World Wide Web Consortium, Web Accessibility Initiative
> Telephone: +1.617.715.4017
> Email: mark@w3.org
> Web: http://w3.org/People/mark
>