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

From: Mark Sadecki <mark@w3.org>
Date: Tue, 08 Apr 2014 16:03:05 -0700
Message-ID: <53448029.5010102@w3.org>
To: Rik Cabanier <cabanier@gmail.com>
CC: "public-canvas-api@w3.org" <public-canvas-api@w3.org>, HTML A11Y TF Public <public-html-a11y@w3.org>, Jay Munro <jaymunro@microsoft.com>, "Rik Cabanier (cabanier@adobe.com)" <cabanier@adobe.com>, Jatinder Mann <jmann@microsoft.com>, Richard Schwerdtfeger <schwer@us.ibm.com>
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?

Thanks,

Mark
> 
> 
> 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
Received on Tuesday, 8 April 2014 23:03:13 UTC

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