- From: Jonathan Kew <jfkthame@googlemail.com>
- Date: Tue, 17 Jul 2012 20:57:59 -0400
- To: Sergey Malkin <sergeym@microsoft.com>
- CC: John Daggett <jdaggett@mozilla.com>, www-style list <www-style@w3.org>, "www-font@w3.org" <www-font@w3.org>
On 17/7/12 19:17, Sergey Malkin wrote: > Rob wrote: >> If CSS 'letter-spacing' is greater than zero, we disable >> discretionary ligatures, because it seems safe to assume that >> matches the author's intent. That behavior could (and I think >> should) be written into the spec. > > This is exactly behavior that should not be in the spec. Why would > you turn off discretionary ligatures, but not standard? I think Rob's use of the term "discretionary" was unfortunate; he did not mean "discretionary ligatures" as typically found in the 'dlig' feature, but rather all ligatures except those that are linguistically required - in other words, in OpenType terms we turn off 'liga', but leave 'rlig' (for Arabic lam-alef forms) enabled. The CSS3 Text spec for letter-spacing says that "[w]hen the resulting space between two characters is not the same as the default space, user agents should not use optional ligatures." I think "optional ligatures" here means ligatures such as "fi" and "fl" that are a typographic refinement in typical Latin fonts, as opposed to ligatures (such as Arabic lam-alef or Devanagari ksha) that are required for correctness in a given writing system. JK
Received on Wednesday, 18 July 2012 00:58:32 UTC