Re: [csswg-drafts] [css-fonts-4] Deduplication of computed style & inheritance for duplicate axis tags

Currently, I believe Gecko passes the specified list of axis-value settings through as-is, and the "last value wins" behavior occurs at rendering time. However, I agree with @upsuper that there's a good case for earlier simplification.

(Note, though, that early simplification of `font-variation-settings` -- e.g. removing duplicates at parsing time -- does not eliminate the need for further processing of the variation list at rendering time, because of how variations specified in a `@font-face` descriptor combine with those specified in an element's style.)

BTW, according to [Fonts 3](https://drafts.csswg.org/css-fonts-3/#propdef-font-feature-settings),

> The computed value of font-feature-settings is a map, so any duplicates in the specified value must not be preserved.

and IMO we should have the equivalent behavior for `font-variation-settings` and `font-feature-settings`; it will be unnecessarily confusing for authors if these two properties behave differently with respect to inheritance, computation, etc.

(I don't have Edge on hand just now to check, but a brief test indicates that neither Gecko nor Blink currently follow the spec here for `font-feature-settings`; duplicates are preserved in the computed value. However, I think we should consider that a bug, and get it fixed accordingly -- for both features and variations.)


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Received on Thursday, 15 February 2018 10:18:27 UTC