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

From: Rik Cabanier <cabanier@gmail.com>
Date: Thu, 17 Apr 2014 11:48:09 -0700
Message-ID: <CAGN7qDA2PDjTWo_9xPELpB3vPvvZ6n1b7gmukVTE_5KP+wH_Vg@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 Thu, Apr 17, 2014 at 11:44 AM, Jay Munro <jaymunro@microsoft.com> wrote:

>  ok, which exception should it throw? There’s a NotSupportedErrjor thrown
> when a path has no pixels, but that doesn’t quite seem right.
>
>
>
> Some other options:
>
> SyntaxError (when arguments isn’t one of the allowed ones)
>
> InvalidStateError  (used when image has no image data)
>
> IndexSizeError (when radii are negative in a radial gradient, other places)
>
> TypeMismatchError (if not an img, canvas, or video with drawImage)
>

Maybe NotSupportedError?
This is what I implemented in firefox


> *From:* Rik Cabanier [mailto:cabanier@gmail.com]
> *Sent:* Thursday, April 17, 2014 11:02 AM
>
> *To:* Jay Munro
> *Cc:* Mark Sadecki; public-canvas-api@w3.org
> *Subject:* Re: Final changes to Hit Regions before return to Last Call
>
>
>
>
>
> On Thu, Apr 17, 2014 at 9:47 AM, Jay Munro <jaymunro@microsoft.com> wrote:
>
> Thanks. Do you have a link to the build you’re looking at, as my source
> has no set of pixels at the beginning of the section.
>
> I’m working on the source from html5_canvas_CR in github.
>
>
>
> I reloaded and now the page is updated. sorry about that!
>
> So, we're good on the 'set of pixels' issue but not the steps for
> 'addHitRegion'
>
>
>
>  *From:* Rik Cabanier [mailto:cabanier@gmail.com]
> *Sent:* Thursday, April 17, 2014 8:36 AM
> *To:* Jay Munro
> *Cc:* Mark Sadecki; public-canvas-api@w3.org
> *Subject:* Re: Final changes to Hit Regions before return to Last Call
>
>
>
> Hi Jay,
>
>
>
> 1. "set of pixels" is still in the spec. It needs to refer to the path in
> the beginning of the section
>
> 2. the steps for addHitRegion don't cover what should happen if there is
> no control or ID. We need an extra step that checks this and throws an
> exception
>
>
>
> Rik
>
>
>
> On Wed, Apr 16, 2014 at 11:38 AM, Jay Munro <jaymunro@microsoft.com>
> wrote:
>
> Mark,
>
> Sanity check before I submit changes.
>
> --Jay
>
>
> -----Original Message-----
> From: Mark Sadecki [mailto:mark@w3.org]
> Sent: Tuesday, April 15, 2014 12:54 PM
> To: public-canvas-api@w3.org; Jay Munro
> Subject: Final changes to Hit Regions before return to Last Call
>
> 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 Thursday, 17 April 2014 18:48:38 UTC

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