[csswg-drafts] [css-fonts-4] issues with font-style oblique font matching

dbaron has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-fonts-4] issues with font-style oblique font matching ==
During the discussion of #2505 today I was looking at the [rules for matching font styles](https://drafts.csswg.org/css-fonts-4/#font-style-matching) in the font matching algorithm related to oblique.

In particular, there are two clauses within 4.2 (which should perhaps be numbered).  One of them (the third overall) starts with:

> If the value of font-style is oblique and the requested angle is greater than or equal to 0deg and less than 20deg,

and the other (the fifth overall) starts with:

> If the value of font-style is normal,

Given the prose elsewhere, this is a little confusing since `oblique 0deg` seems to be defined as equivalent to `normal`, yet one of these clauses covers one and one covers the other.  I think this should be clearer (or maybe the other wording about equivalence should be different... I guess we discussed that earlier).

Further, there are some issues with the first of them:
* subpoint 2 says "until 0 is hit", but it's not clear if that's inclusive or exclusive (though I feel like it has to be given that the clause as a whole is inclusive of 0)
* subpoint 4 does clearly include 0, and it seems problematic that clauses 2 and 4 both include 0
* for whichever includes 0, it's not clear whether `normal` fonts (rather than `oblique 0deg` fonts) count (though based on the *second* of the clauses I mentioned, i.e., the fifth overall, I think it's clear that it does, but it should be clearer locally)

Some of this is probably better fixed by linking to definitions than by adding too much additional wording.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2541 using your GitHub account

Received on Wednesday, 11 April 2018 15:36:19 UTC