Contact emails e...@igalia.com, fw...@igalia.com
Explainer None Specification https://w3c.github.io/mathml-core/#layout-of-operators Summary Support for character-level and glyph-level mirroring when rendering MathML operators in right-to-left mode. When using RTL mode some operators can be mirrored by changing them to another code point (eg a right parentheses becomes a left parentheses). This is character-level mirroring, with equivalences defined by Unicode's `Bidi_Mirrored` property. There are operators that have no appropriate mirroring character. Glyph-level mirroring applies in this case, with the `rtlm` font feature, where another glyph can replace it in a mirrored context. Some existing implementations mirror the original glyph directly, but this may change the meaning for asymmetrical characters, such as the clockwise contour integral. Blink component Blink>MathML Motivation Arabic mathematical notations require rendering math operator in right-to-left mode, where operators need to be correctly mirrored. Sometimes, a simple horizontal flip is not enough. In the case of asymmetrical glyphs like a clockwise contour integral doing so would change the meaning of the symbol. That's why both character-level mirroring and glyph-level mirroring is needed to produce a correct mathematical expression in RTL mode. The following explainer shows the different cases to consider when mirroring stretchy characters, as well as the proposed MathML Core spec amendments to support this use case: https://people.igalia.com/fwang/mathml-operator-mirroring-explainer.html Initial public proposal None TAG review None TAG review status Not applicable Risks Interoperability and Compatibility None Gecko: No signal At the moment doing simple flipping. There is a working implementation of both character-level and glyph-level mirroring. WebKit: No signal Already has character-level mirroring. rtlm not supported, using flipping as a fallback. Web developers: No signals Other signals: WebView application risks Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications? None Debuggability None Is this feature fully tested by web-platform-tests? Yes New tests: - Character-level mirroring: checks that when switching text direction the codepoints of the characters change to the corresponding BidiMirrored equivalent (eg right to left parentheses) - Glyph-level mirroring: checks that the rtlm font feature is supported and that a specific glyph is used for certain characters when switching text direction. Flag name on about://flags None Finch feature name None Non-finch justification None Requires code in //chrome? False Tracking bug https://issues.chromium.org/issues/40120782 Estimated milestones No milestones specified Link to entry on the Chrome Platform Status https://chromestatus.com/feature/6317308531965952?gate=5188425870999552 This intent message was generated by Chrome Platform Status. -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/686d2758.170a0220.a35ba.00d7.GAE%40google.com.
