[webkit-dev] MathML Refresh Heads up

Fri Mar 15 16:29:22 PDT 2019

> On Mar 15, 2019, at 3:33 PM, Frédéric Wang <fwang at igalia.com> wrote:
> 
> Hi Ryosuke and Myles,
> 
> Thank you for your reply. First, the exact thing about what will be in MathML Core is still open, people are welcome to join and participate to the MathML CG [1] or comment on the GitHub tracker [2].
> 
> Our plan was also to remove features from WebKit but of course ultimately the consensus has to be made in the WebKit community (hence our heads up email). What do you suggest? Should we send "intent to remove" to this mailing list? Or is it enough to cc' Apple reviewers on bugs in order to get the approval? Something else?

It’s easier for us to check Apple Books and iOS App compatibility for a batch of possible removals at once, instead of one at a time. We can start by looking at the set of items below.

It’s helpful to give a heads-up other than the normal review process, because our main concern is compatibility, and not all reviewers will be able to easily access the corpus of app-specific or books-specific content that may be affected. 

We assume web compatibility is not a major issue since MathML isn’t in all browsers and in general is not widely used on websites, but there might also be some value in doing web usage analysis for these features if there’s any meaningful web usage of MathML at all.

> 
> For now, these are the features the CG has already agreed to not include in MathML Core (more to come). We would like to propose to remove them from WebKit:
> 
> * "thin", "thick", "medium" values of mfrac's linethickness attribute ( https://github.com/mathml-refresh/mathml/issues/4 <https://github.com/mathml-refresh/mathml/issues/4> )
> * "small" "normal" "big" values of mathsize attribute ( https://github.com/mathml-refresh/mathml/issues/7 <https://github.com/mathml-refresh/mathml/issues/7> )
> * nonzero unitless values for MathML lengths ( https://github.com/mathml-refresh/mathml/issues/24 <https://github.com/mathml-refresh/mathml/issues/24> )
> * fontfamily, fontweight, fontstyle, fontsize, color, background MathML attributes ( https://github.com/mathml-refresh/mathml/issues/5 <https://github.com/mathml-refresh/mathml/issues/5> )
> 
> In any case, it would be very appreciated to get some analysis about the usage of MathML markup used in Apple's product. How can we proceed to obtain it?
> 
> Thanks,
> 
> [1] https://www.w3.org/community/mathml4/ <https://www.w3.org/community/mathml4/>
> [2] https://github.com/mathml-refresh/mathml/issues/ <https://github.com/mathml-refresh/mathml/issues/>
> 
> On 15/03/2019 22:33, Myles C. Maxfield wrote:
>> 
>> 
>>> On Mar 15, 2019, at 11:29 AM, Ryosuke Niwa <rniwa at webkit.org <mailto:rniwa at webkit.org>> wrote:
>>> 
>>> 
>>> On Fri, Mar 15, 2019 at 3:08 AM Frédéric Wang <fwang at igalia.com <mailto:fwang at igalia.com>> wrote:
>>> Hello WebKit developers,
>>> 
>>> As some of you may know, Igalia is working on MathML support in Chromium
>>> this year [1]. As part of that effort we joined a new MathML Refresh
>>> Community Group [2] and one goal is to focus on a core spec for browser
>>> implementations [3] to:
>>> - Remove deprecated/uncommon/duplicate math features that could be
>>> implemented by polyfills (relying on MathML core and other web
>>> technologies).
>>> 
>>> I'd be very much concerned about backwards compatibility here when it come to removing any features.
>>> It's important to notice that WebKit is also used by hundreds of thousands of iOS apps and macOS apps.
>>> How do we know we won't break those applications?
>>> 
>>> In general, I don't agree with whatever Google said about MathML being too complex, etc…
>> 
>> The original sentence doesn’t say they will be removing anything in WebKit. There are plenty of features that have been removed from specs that we continue supporting in WebKit for backwards compatibility.
>> 
>> We could also consider migrating our implementation to a JS polyfill if one exists.
>> 
>> Is there a characterization of which features are planned for deprecation? We might be able to do some analysis on iBooks' and iOS apps’ content.
>> 
>>> 
>>> - Add more detailed algorithms (based on TeX/OpenType/CSS layout) to
>>> help implementation and conformance testing.
>>> - Align MathML with CSS/HTML (parsing, layout...), introducing new web
>>> platform features (CSS, fonts...) for math if necessary.
>> 
>> This sounds wonderful! A more coherent MathML story going forward would be fantastic.
>> 
>>> 
>>> On the other hand, these seem like very valuable improvements.
>>> 
>>> We expect that this effort will improve browser interoperability and
>>> reduce complexity of current implementations.
>>> 
>>> Given there aren't too many websites that deploy MathML directly on production, my concerns are more about existing iOS and madOS apps that embed WKWebView or WebView / UIWebView and use MathML.
>>> 
>>> - R. Niwa
>>> 
>>> _______________________________________________
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>>> https://lists.webkit.org/mailman/listinfo/webkit-dev <https://lists.webkit.org/mailman/listinfo/webkit-dev>
>> 
> 
> -- 
> Frédéric Wang
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