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

From: Rik Cabanier <cabanier@gmail.com>
Date: Mon, 28 Apr 2014 10:48:29 -0700
Message-ID: <CAGN7qDAfW6j-0EDB2qLL6xfbk_jiDxQxBD2WYke_8CqNwaLnEQ@mail.gmail.com>
To: Jay Munro <jaymunro@microsoft.com>
Cc: Mark Sadecki <mark@w3.org>, "public-canvas-api@w3.org" <public-canvas-api@w3.org>
On Mon, Apr 28, 2014 at 10:28 AM, Jay Munro <jaymunro@microsoft.com> wrote:

>  Rik,
>
>
>
> I see it responds to a mousemove event, which was something we wanted but
> thought might be difficult. Looks like it covers it nicely.
>

Thanks!

Yes, any event that derives of the mouse event should now support the
region attribute.
The hard part was the retargeting which we're postponing to level 2


>
>
> *From:* Rik Cabanier [mailto:cabanier@gmail.com]
> *Sent:* Monday, April 28, 2014 8:42 AM
> *To:* Mark Sadecki
> *Cc:* public-canvas-api@w3.org
> *Subject:* Re: Final changes to Hit Regions before return to Last Call
>
>
>
> Hi Mark,
>
>
>
> I implemented a prototype implementation of hit regions in Firefox. It has
> not landed in FF Nightly yet, but that should happen shortly.
>
> Here's a build for windows:
> http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/cabanier@adobe.com-7c242c5e96ce/try-win32/firefox-31.0a1.en-US.win32.zip
>
> and for mac:
> http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/cabanier@adobe.com-7c242c5e96ce/try-macosx64/firefox-31.0a1.en-US.mac.dmg
>
>
>
> After downloading, set the hitregions flag to true (about:config ->
> canvas.hitregions.enabled) and restart.
>
> Here's an example: http://codepen.io/anon/pen/zEsxa?editors=101
>
> Hovering over the areas, should update the text with the ID of the area.
> The regions should also be accessible to a11y tools.
>
>
>
> Please let me know if this is behaving as expected, especially the a11y
> part.
>
>
>
> Rik
>
>
>
> On Tue, Apr 15, 2014 at 12:53 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 Monday, 28 April 2014 17:49:00 UTC

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