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On Tue, Oct 01, 2013 at 11:20:52AM +0200, Hans Hagen wrote:
On 10/1/2013 10:05 AM, Marco Patzer wrote:
On 2013–09–30 Hans Hagen wrote:
these are unrelated mechanisms where the first one just does some pdf magic ... no feedback to tex about widths (ok, i could write something better but never had and still don't have a reason for that kind of low level pdf based approach to be really deeply integrated)
Thanks for the explanation. I was looking for a way to do slight letter spacing without breaking ligatures and thought I could leverage the stretch effect for that.
well, we break ligatures because ligatures make no sense in that kind of kerned text (if they make sense at all, but that's a different issue
Some ligatures should not be broken in letter-spaced text, typically represented by rlig in OpenType, e.g. Fraktur ch, ck, ſt and tz ligatures: http://unifraktur.sourceforge.net/letterspacing.html
When using the characterkerning method you can exempt ligatures and character pairs from being letterspaced by defining the functions typesetters.kerns.keepligature (<liganode>) and typesetters.kerns.keeptogether (<prevglyph>, <glyph>), respectively. If the function returns a truish value for the given input, ligatures won’t be decomposed and no extra kerning will be applied. Best regards Philipp