- From: jfkthame via GitHub <sysbot+gh@w3.org>
- Date: Thu, 04 Feb 2021 12:55:29 +0000
- To: public-css-archive@w3.org
The browser should account for what it knows about the display properties and expected viewing conditions when determining the mapping from CSS pixels to display pixels. The author should usually trust the combination of the browser and the font designer, and let automatic optical sizing do its thing. But I think there are reasonable arguments for allowing the author to override this when desired, and request a specific optical sizing effect that may differ from the default. The basis on which the author does this may be questionable sometimes: e.g. an author might set a large `font-optical-size` value for small text when the typographic effect they're aiming for would have been more accurately described as a lighter `font-weight` and an adjustment to `letter-spacing`. But that's not our concern; almost every design property can be "misused" in some way. More legitimately, an author (or web app) may know that the text they're dealing with is going to be scaled at some level in the rendering stack, so that the most appropriate optical size might be different from the nominal `font-size` being used. For example, if I know that a CSS `transform: scale(2)` is going to apply to some content, I might want to set `font-optical-size: 2em` in preparation for that. (Or I might not, depending on the effect I'm going for.) Or if I know that some content is going to have an animated `font-size`, I might want to apply an absolute `font-optical-size` to it so that the glyphs scale linearly -- again, depending on the specific effect desired. (The problem of the author not knowing exactly how the page will be viewed is not very different from what has always existed for print: when designing an A0-sized poster, do I design for the individual standing directly in front of it, maybe 3 feet away, or for the group 20 feet back? What optical size should I use for the headline? For secondary content? Those decisions are rather arbitrary, and we need to let designers make them according to whatever criteria they choose.) -- GitHub Notification of comment by jfkthame Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/4430#issuecomment-773284309 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Thursday, 4 February 2021 12:55:31 UTC