[css3-writing-modes] text-combine: cluster

The current draft of the CSS3 Writing Modes spec includes a 'cluster'
value for the text-combine property.  It's not entirely clear from the
spec what is intended for this value but talking to Koji this appears to
be intended to support specific ligatures for things like units.  These
are already supported as ligatures in fonts today and I don't think it
makes sense to have browsers try and synthesize them on the fly.  There
are also both horizontal and vertical forms of these, they are not
specific to vertical text.  In terms of the CSS3 Fonts spec
properties, these can be accessed via:

  span.unitligs { font-variant-ligatures: additional-ligatures; }

Browsers supporting writing-mode would enable vertical features for OpenType fonts, so both horizontal and vertical forms would be displayed appropriately.

The latest Firefox nightlies support OpenType features which can be used to
enable these ligatures:

  http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/

With the latest nightly, view this example:

  http://people.mozilla.org/~jdaggett/tests/kumimoji.html

John Daggett

Received on Tuesday, 26 October 2010 02:32:02 UTC