RE: Add 'manipulation' touch-action property?

With my implementer’s hat on, I see little value in the change for end developers. I don’t have an issue with changing our implementation, but it may be a while before I can get this fix prioritized just given its near zero impact.

Arguably, if someone is specifying “manipulation pan-x”, then they do not properly understand the meaning of the values are on a failure path. In that light, it’s perhaps better that the rule fail outright signaling to the developer in testing that they’ve made a mistake.

From: Rick Byers [mailto:rbyers@google.com]
Sent: Monday, March 10, 2014 5:04 PM
To: Jacob Rossi
Cc: public-pointer-events@w3.org; ext Matt Brubeck; Patrick H. Lauke; Nikolay Lebedev
Subject: RE: Add 'manipulation' touch-action property?


If the compat risk is low, then perhaps we should consider using the more logical definition?  IE would of course be free to continue to implement a superset of the specd grammar.
On Mar 10, 2014 4:37 PM, "Jacob Rossi" <Jacob.Rossi@microsoft.com<mailto:Jacob.Rossi@microsoft.com>> wrote:
On Fri, Mar 7, 2014 at 2:38 PM, Rick Byers <rbyers@google.com<mailto:rbyers@google.com>> wrote:
>
> On Fri, Mar 7, 2014 at 5:30 PM, Jacob Rossi <Jacob.Rossi@microsoft.com<mailto:Jacob.Rossi@microsoft.com>> wrote:
>>
>> The MSDN docs certainly don’t match our implementation (we’ll fix that).  The spec’s current grammar does match our implementation.
>>
>>
>>
>> I agree it’s a tad quirky that “manipulation pan-x” works but “pan-x pan-x” doesn’t (seeing as manipulation is essentially shorthand for “pan-x pan-y other-goo”. “auto” / “none” are typically never combinable with other values in any property though.
>>
>>
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>> While it is probably sub-optimal, It passes the “I can live with it” test for me too.
>
>
> I assume changing this has a non-trivial risk of breaking some website, right?  Do you have any data on this?  I can query the google search index for sites that specify them together in CSS if you think there's a chance we'd change the spec and IE behavior if it was found to be sufficiently non-breaking.  If we can be confident that it's unlikely to break anyone, then we might as well make it right - no?  I.e. we should only apply the "I can live with it" test if there's some reason to live with it :-)

The results I have from Bing yielded no known usage of "touch-action: <something> manipulation;" or "touch-action: manipulation <something>;". That only covers statically defined properties; but in my experience with compat and touch-action this has shown to be a sufficient measure. This also assumes my regex fu was strong. :-)

touch-action:([\s]*[a-z-]+[\s]manipulation)|([\s]*manipulation[\s]+[a-z-]+)[\s]*;