Re: [csswg-drafts] [css-fonts] Reconsider the definition of "first available font" (#4796)

The CSS Working Group just discussed `[css-fonts] Reconsider the definition of "first available font"`, and agreed to the following:

* `RESOLVED: Amend our algo for selecting first available font to check for the 0 glyph, if not there check for notdef glyph, else use 0.5em`
* `RESOLVED: Remove previous resolution, discussion continues on github`

<details><summary>The full IRC log of that discussion</summary>
&lt;dael> Topic: [css-fonts] Reconsider the definition of "first available font"<br>
&lt;dael> github: https://github.com/w3c/csswg-drafts/issues/4796<br>
&lt;dael> chris: Not all fonts have glyph for space which means not first available font<br>
&lt;dael> chris: Prop is a three way thing where thirds is width of notdef glyph which all fonts are required to have<br>
&lt;dael> astearns: I see that's 2nd on list<br>
&lt;dael> chris: Yes, sorry<br>
&lt;dael> astearns: If notdef is guar?<br>
&lt;dael> TabAtkins: Required and there are different. I'm happy with this<br>
&lt;dael> astearns: Is it what browsers impl?<br>
&lt;dael> chris: We believe so<br>
&lt;dael> chris: There's a WPT that's wrong right now but it would become correct with this change. I suspect that means browsers do what this is proposed<br>
&lt;dael> astearns: Prop: Amend our algo for selecting first available font to check for the 0 glyph, if not there check for notdef glyph, else use 0.5em<br>
&lt;dael> astearns: Objections?<br>
&lt;dael> RESOLVED: Amend our algo for selecting first available font to check for the 0 glyph, if not there check for notdef glyph, else use 0.5em<br>
&lt;dael> chris: My proposal is in the issue comments<br>
&lt;dael> fantasai: I think ti's different then original proposal so wondering if he was okay. I've got your proposal and one from Johnathan<br>
&lt;dael> chris: Right, his inclues unicode range so if the unicode range excludes space. Not about if font excludes space then it counts as not having one.<br>
&lt;dael> astearns: And if you use unicode range you exclude notdef so it falls to 0/5em<br>
&lt;dael> chris: notdef isn't excludable with unicode range<br>
&lt;dael> fantasai: resolution defines ch unit but first available font is a lot more general. I'm a little confused. 4796 from what I understand is the new definition is first space checking for first space. He prop not checking if there's a space but if unicode range on font would cover space character. THen you prop check for 0<br>
&lt;dael> chris: Not quite. If it doesn't have a 0 then you can use notdef glyph rather then say we fail. That's compat with webkit<br>
&lt;dael> fantasai: So to find first available font I check for a space, then for a 0, then notdef glyph, then use 0.5em? 0.5em is not a font.<br>
&lt;dael> chris: Right. I see what you're saying.<br>
&lt;dael> astearns: Talking about how to determine a measure from a first available font without a space or a 0 or notdef<br>
&lt;dael> fantasai: ch has a definition of use 0 or 0.5em. If you're looking for x there's other metrics. Here we're looking for what font file.<br>
&lt;dael> astearns: We're over-time. We should undo previous resolution and bring up later<br>
&lt;dael> RESOLVED: Remove previous resolution, discussion continues on github<br>
</details>


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Received on Thursday, 5 March 2020 01:02:57 UTC