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

> But the text is an actual, physical size, which is what the optics of the reader is seeing, and which optical size is supposed to address. 

Per Miles in 2017, there are 4 different zoom modes in Safari (https://github.com/w3c/csswg-drafts/issues/807#issuecomment-285703481), so while it is trivially true that any text is an actual, physical size, the 'logical' size is what optical size is supposed to address. Highway signage has letters physically a meter tall, but they are logically small-size and closer to caption or dictionary letters. 

> What we disagree about, I think, is the implication of that decision. It isn't just a change to a different unit, but from an absolute, physical unit to an uncertain flexi-unit. 

Do you agree that the flexi part is handled by `font-optical-sizing: FLOAT`?

> Redefining the opsz scale to use px as a unit means redefining it as not optical. Yes, we can say that Mac OS is the oddity in the way it makes a kind of px and a kind of pt equivalent, and hence the size of px on that platform vs other platforms, but I'm not left with any reassurance that it is the only oddity or will remain the only oddity. 

Sure, but that's why the proposal is for extending `font-optical-sizing` to accept a FLOAT number value, and not merely extending the ENUM values from `auto, none, inherit, initial, unset`, to include `apple`, and then have to extend it as more oddities become culturally significant enough to warrant inclusion.

> Once you have a flexi-unit, you really can't make any assumptions or predictions.

Yes, you can; you can predict what a 1000 UPM glyph drawing will do when quantized to a 12 css px size grid and a 16 css px size grid and a 144 css px size gri.

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Received on Thursday, 28 May 2020 15:09:42 UTC