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Re: [csswg-drafts] [css-fonts] Proposal to extend CSS font-optical-sizing (#4430)

From: jfkthame via GitHub <sysbot+gh@w3.org>
Date: Wed, 16 Sep 2020 19:58:07 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-693632783-1600286286-sysbot+gh@w3.org>
> > My suggestion would be to add two keywords, `px` and `pt` to `font-optical-sizing`
> This is fundamentally an incorrect design. `font-optical-sizing: auto` means "set it to whatever it needs to be to get good typography" which will end up being different values on different operating systems. For the same CSS content, browsers on different operating systems should set `opsz` to different values in order to match the coordinate systems of those operating systems. Having the spec say specifically "use `px`" or "use `pt`" will be wrong on half the OSes.

As I understand it, you're arguing that given content styled with `font-size: 12pt`, a browser running on macOS should apply opsz=16, while a browser running on Windows should use opsz=12 (right?).

Now, I can view that same web page using either my Mac or my Windows PC  -- I can even connect the exact same display to either of them, and potentially see the content at the same physical size (depending on the OS-level resolution settings I've chosen). It seems regrettable that in these circumstances, the two browsers will be expected to use _different_ opsz values and therefore may get significantly different glyphs.

Maybe we're stuck with this, but it's an unwelcome inconsistency. I think it's reasonable for an author to want to override it and request a consistent behavior -- whether that's "opsz = CSS px" or "opsz = CSS pt" -- across platforms. And it shouldn't be necessary to use a `font-feature-settings` override to achieve this.

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Received on Wednesday, 16 September 2020 19:58:08 UTC

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