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

Second, I now advocate updating the OpenType spec to document what is actually implemented. @Lorp put it concisely:

opsz = font-size in px for screen media
opsz = font-size in pt for print media

You advocate making design for optical size impossible? Type designers have to be able to target specific sizes in a reliable unit, and to assign those designs to values on a reliable scale. How that scale gets interpreted and translated into other units is outside our control, but _something_ needs to be in our control so we can do our job. We cannot design for a specific size and map it to e.g. opsz=9 if that means 9 px in screen media and 9 pt in print media. Trying to do so is no longer optical size design, it’s vaguely-bigger–or–smaller design.

As I wrote [earlier](, I’m okay with fuzzy interpretation of opsz in browsers, because it’s characteristic of the medium that things at the same nominal size are different sizes in different places, but that fuzziness belongs at the interpretation and implementation level—where it can be more or less precise, more or less faithful to the opsz spec and the type designer’s intent as the implementor chooses—and not baked into that spec in a way that makes the whole concept of opsz design meaningless.

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Received on Thursday, 8 July 2021 20:35:00 UTC