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

> If I understand correctly, what these options do is redefine the unit value of the opsz variations axis.

Yes.

> we've already got massive confusion over the actual unit value of the axis and how it should be interpreted for auto

Browsers may not yet have stabilised yet on how they behave in `auto` mode, as @jfkthame notes. Until his observation, we were under the assumption that browsers reliably use `px` for screen media and `pt` for print media for their calibration of the `opsz` axis.

Nevertheless, a clear CSS specification with manual options can help clarify the parameters that `auto` uses, clarification necessary for CSS authors, CSS spec authors, user-agent authors and producers of fonts.

So far we have been talking about `auto` effectively choosing `px` or `pt` depending on `@media` context (i.e. screen or print … that‘s what I meant by my brief comment “get font-size in pt or px”), but in principle it could be influenced by other factors such as physical screen size, viewer distance and accessibility settings. And that’s ok.

Using either the `px` or `pt` keywords would specify that `font-size` (in `px` or `pt` respectively) should be the only factor in determining optical size and the value should be used directly as the `opsz` axis value.

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Received on Wednesday, 23 September 2020 21:40:37 UTC