Re: [csswg-drafts] @font-face overrides for superscript/subscript metrics (#5518)

I'm worried about "must" language requiring browsers to switch away from browsers' hardcoded formula in favor of data provided by the authors. It seems to me that bogus data can occur in CSS just as easily as it can occur in font files. (This proposal seems to be about fixing the problem of bogus data, as compared to `ascent-override` which is about fixing the problem in incompatible, but not bogus, data.)

However, a browser has the ability to ignore any property or descriptor if it believes doing so is in the interest of the user, regardless of whether or not the spec uses "must" language. It seems to me that, even if the spec says "must", if the webpage puts something crazy in there, the browser would still be within its rights to ignore it and use a hardcoded formula. This is already the case (i.e. "implementation limits") for many (all?) existing properties.

From an author's perspective, "must" language would probably be a good thing, as they want to provide some fairly strong signal that what they put in their CSS is actually going to be used (assuming they don't do anything crazy).

So I think I would be positive on using "must" language, like @fantasai proposed in

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Received on Wednesday, 30 September 2020 06:47:47 UTC