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Re: Touch-action to SVG elements

From: Rick Byers <rbyers@google.com>
Date: Tue, 25 Mar 2014 12:23:39 -0400
Message-ID: <CAFUtAY8vHPOSqrn3zDZveLfXTqroDRRQ-Ohsni-BFdz2bB=JDA@mail.gmail.com>
To: Jacob Rossi <Jacob.Rossi@microsoft.com>
Cc: "public-pointer-events@w3.org" <public-pointer-events@w3.org>, "gnanasekar.s@samsung.com" <gnanasekar.s@samsung.com>, Douglas Schepers <schepers@w3.org>
Thanks Jacob!

To re-iterate what I said on the call today: this definition seems fine to
me, we'll update our implementation to match after the draft spec has been
updated.  Blink bug: https://crbug.com/356215

Thanks,
  Rick


On Fri, Mar 21, 2014 at 3:09 PM, Jacob Rossi <Jacob.Rossi@microsoft.com>wrote:

> Following up on this thread (and action 65).
>
> From: Rick Byers <rbyers@google.com>
> Date: Fri, 17 Jan 2014 11:17:47 -0500
>
> > *Jacob, *do you agree that the behavior we see in IE is what we want the
> spec to describe (touch-action supported on <svg> elements, but not other
> types of SVG elements)?
>
> Yes.
>
> > *Jacob/Doug*, what's the right wording to convey this precisely?  My
> reading of the SVG spec is that "SVG elements" includes things like <path>,
> etc.
> >
> > In addition, it seems IE applies touch-action on inline-block elements
> (which I think makes sense).  My reading of the CSS spec is that
> inline-block isn't necessarily included with "block level elements".  Is
> there a more precise term to encompass display: block and display:
> inline-block?
> >
> > What about the other display types that establish a BOX but aren't
> themselves BLOCKS (eg. table-row, table-cell), what's the expected behavior
> for them?  Sorry I'm not enough of a CSS expert to know the precise terms
> we're looking for here (and it wasn't obvious to me from the CSS spec).
>
> I consulted with some of our CSS WG reps and also did testing to confirm
> IE's behavior. It looks like <svg> shouldn't be a special case. It is no
> different than <img>, which is a replaced inline element (not block-level)
> and supports touch-action. So the current spec text is incorrect.
>
> The correct definition should match that of the intersection of the height
> and width properties from CSS2.1 [1,2]:
>      Applies to:  all elements but non-replaced inline elements, table
> rows, row groups, table columns, and column groups
>
> Put another way, it applies to any element that *both* width and height
> apply to in CSS. Note table rows only accept height and table cols only
> accept width, therefore touch-action applies to neither by this definition
> (also cols are effectively display: none; so they were already irrelevant).
>
> This means block elements (like div), inline-block elements (like button),
> replaced inline elements (like img, svg, canvas, video), tables, and table
> cells/headers/captions are supported. But non-replaced inline elements
> (like span), table col/row elements, and table col/row groups are not
> supported.
>
> I propose we change the spec to match the applies to text above. Testing
> briefly [3] Chrome, it looks like the replaced inline elements (img, svg,
> canvas, etc) and input controls aren't supported but should be. Firefox has
> the same issue as Chrome, except that <img> is already correctly supported.
> We should probably convert this page into an actual test case.
>
> -Jacob
>
> [1] http://www.w3.org/TR/CSS21/visudet.html#the-width-property
> [2] http://www.w3.org/TR/CSS21/visudet.html#the-height-property
> [3] http://jsfiddle.net/S9C5Y/3/embedded/result/
>
Received on Tuesday, 25 March 2014 16:24:27 UTC

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