- From: John Daggett <jdaggett@mozilla.com>
- Date: Sun, 20 Feb 2011 22:38:00 -0800 (PST)
- To: Koji Ishii <kojiishi@gluesoft.co.jp>
- Cc: www-style@w3.org
Koji Ishii wrote: > When source text contains Unicode Variation Selector[1][2][3], > how does that affect font choice for the code point? > > Here's an example. With the following style: > font-family: A B; > and let's say both fonts contains the glyph for U+8FBA, but > only font B contains VS1 of U+8FBA. > > For the source text of U+8FBA VS1, should font A be used to > render it, or B? > > I assume font B, as font A does not contain the glyph the > author specified and ignores VS1, but I'd appreciate > clarification since Variation Selector can behave differently > from the regular code point for font fallback. As John Hudson has described, I think the answer here is A, in other words the user agent does not search through the font list until it has found a font which supports a given variation selector, it always chooses the first font that contains a glyph for the underlying character. This is the way it's implemented in Firefox 4, which has UVS support on all platforms. Here's an example reftest: http://people.mozilla.org/~jdaggett/font-face/ivs-1.html http://people.mozilla.org/~jdaggett/font-face/ivs-1-ref.html There's a certain amount of overlap here between UVS and various font-variant values (e.g. jis78, character-variant). Those work the same way, if a font contains a glyph for the underlying character but doesn't support a variant, the default glyph is used rather than falling back. But I agree UVS handling should be explicitly detailed in the spec. Regards, John Daggett
Received on Monday, 21 February 2011 06:38:32 UTC