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

From: Jay Munro <jaymunro@microsoft.com>
Date: Tue, 8 Apr 2014 22:43:34 +0000
To: Mark Sadecki <mark@w3.org>, "public-canvas-api@w3.org" <public-canvas-api@w3.org>
CC: HTML A11Y TF Public <public-html-a11y@w3.org>, "Rik Cabanier (cabanier@adobe.com)" <cabanier@adobe.com>, Jatinder Mann <jmann@microsoft.com>, Richard Schwerdtfeger <schwer@us.ibm.com>
Message-ID: <b6913da603af4737aed9026b0fa77039@BY2PR03MB521.namprd03.prod.outlook.com>
I've updated the issues on clearHitRegions() and moving the clearRect and clearHitRegions. I just submitted. 

-----Original Message-----
From: Mark Sadecki [mailto:mark@w3.org] 
Sent: Tuesday, April 8, 2014 2:56 PM
To: public-canvas-api@w3.org
Cc: HTML A11Y TF Public; Jay Munro; Rik Cabanier (cabanier@adobe.com); Jatinder Mann; Richard Schwerdtfeger
Subject: Questions RE: Hit Regions before return to Last Call

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.

# 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].
>> Jay:  done 

# 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.
>>Jay: Done

# 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.

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
Email: mark@w3.org
Web: http://w3.org/People/mark
Received on Tuesday, 8 April 2014 22:44:05 UTC

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