Re: [csswg-drafts] [css-text-decor] ink skipping should conform to glyph shape

A SHOULD clause would make it clear that conforming to the shape is the intended (goal) rendering. It looks nicer is one reason, but it also helps distinguish underline vs. diacritics, so following the outline is definitely the better option. However, RFC2119 SHOULD allows UAs to deviate if they have a well-thought-out reason to do so, and the perf concerns here qualify. https://www.ietf.org/rfc/rfc2119.txt

Wrt handling floaty things, I think saying" stroke endings should follow the curve of the glyph" is sufficiently lenient: the ideal rendering would probably be something like: UA determines where it can place underline segments by where a full-height underline segment of some minimum length would fit, and then each such segment's stroke ends are made to conform to the glyph outline. (Not suggesting we spec that exactly, just that such behavior would be conformant and reasonable.)

I do agree with @tobireif that not all underlines are thin (especially once we add `text-decoration-width` in L4), and in such cases the perf tradeoff would be more worth it. A UA that cares enough to implement the ideal behavior could switch it on above a certain threshold to maintain perf for the common case, though.

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Received on Monday, 13 March 2017 20:01:54 UTC