Re: [w3ctag/design-reviews] Review MathML (#313)

Summary of our plan:

(1) We know that the MathML specification has design issues and is currently no longer maintained by the Math WG. Instead of just throwing it away and restarting something from scratch, we want a smooth transition to make it more aligned with the rest of the Web platform. The implementation note that we used for WebKit was one step in that direction and we are willing to do more. Basically, our idea is to extract a core subset (with some hints on how to keep backward compatibility for existing documents) and rely as much as possible on HTML5/CSS features (refining the implementation note while new features are introduced). Finally, TeX/OpenType algorithms/features and WPT tests are essential to provide accurate and consistent rendering across browsers. This is harder if one lets Web developers implement and maintain their own math rendering.

(2) Google is pushing for Houdini and layered APIs but things are far from being ready. In particular, they think they will only ship basic LayoutNG support in a few months and things like a font API (instrumental for math layout) are still in the planning stage. However, we agree with Google's layout team that this new layout approach is a good path forward. The plan is to start with a C++/LayoutNG-based implementation of MathML in order to see how much we are able to do while introducing new APIs as needed. In particular, an abstraction layer for HarfBuzz's OpenType MATH API would be helpful for the Houdini fonts API and to ensure it is good enough to fulfill the needs of math rendering. In the future, we could move to higher level implementations, always being careful that the WPT tests do not break and that we don't have significant performance regressions compared to the pure C++ implementations. 

(3) Apple and Mozilla's plans for Houdini and Layered APIs are not clear at the moment. However, WebKit and Gecko already have MathML implementations. Our short-term plan is to refine/cleanup these implementations based on the standard evolution we are going to make in (1) and in the future we could rely on the outcome of (2) to further improve the implementations.


-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/w3ctag/design-reviews/issues/313#issuecomment-435056946