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Re: Final changes to Hit Regions before return to Last Call

From: Richard Schwerdtfeger <schwer@us.ibm.com>
Date: Wed, 16 Apr 2014 14:36:24 -0600
To: "Mark Sadecki" <mark@w3.org>
Message-ID: <0CF7914F-98AE-4B37-B218-514363EA600D@us.ibm.com>
Cc: "public-canvas-api@w3.org" <public-canvas-api@w3.org>, "Jay Munro" <jaymunro@microsoft.com>


I am on vacation and with limited access to email but didn't we decide to
dispatch the event to the actual control in v1.0? Rather, I thought the id
of the target would be included in The dispatch to the canvas element.

Rich

Sent from my iPad

> On Apr 15, 2014, at 3:53 PM, "Mark Sadecki" <mark@w3.org> wrote:
>
> The following changes were discussed during the canvas accessibility sub
group
> call on 14 APR 2014
>
> <http://www.w3.org/2014/04/14-html-a11y-minutes.html>
>
> ## The region representing the control
>
> * Add a step that handles a null value for control, similar to the one
that is
> defined for ID, just before the existing step 1.
>
> > "If control is null, return nothing and abort these steps."
>
> ## The region for a pixel
>
> * Change "set of pixels" to "path" in step 2 and link "path" to
>
<http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas_CR/#hit-region%27s-path>

>
> ## addHitRegion()
>
> * add the following step after step 3 (Let specified pixels be the pixels
> contained in source path.)
>
> > "Remove from specified pixels any pixels not contained within the
clipping
> region."
>
> ## clearHitRegions()
>
> * Remove Step 2 RE: Garbage Collection
>
> ## MouseEvent
>
> We agreed that we would eliminate event retargeting altogether and just
pass the
> event.region to the canvas element.  This would require the following
changes:
>
> * Revert order of steps and add step for handling a canvas element with
no hit
> region list.  The first 4 steps should read as follows:
>
>    1. If the pointing device is not indicating a pixel on the canvas, act
as
> normal and abort these steps.
> -> 2. If the canvas element has no hit region list, act as normal and
abort
> these steps.
>    3. Let pixel be the pixel indicated by the pointing device.
>    4. Let region be the hit region that is the region for the pixel pixel
on
> this canvas element's bitmap, if any.
>
> * The following steps are no longer required (the numbers will be shifted
by one
> if the above steps have been followed) and should be removed:
>
> 7. Let control be the region's control, if any.
> 8. Let the canvas element be the target of the event object, unless there
is a
> control, then target the control instead.
> 9. Continue dispatching the event, but with the updated event object and
target
> as given in the above steps.
>
> --
> 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 Wednesday, 16 April 2014 20:36:57 UTC

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