Ligatures sorting

Konstantinos Siskakis

I'm going to create a font with ligatures and I was wondering if and how popular applications (like FL or Glyphs) sort them. For example, if there are ligatures with five, four, three, or two glyphs I  would like the ones with the most glyphs to precede those with less. Is that possible?

Kent Lew

What do you mean by “sorting”?

If you are asking how to insure that the largest possible ligature gets substituted in a given sequence, the AFDKO automatically reorders the compilation of GSUB Type 4 lookups to provide for this.

A contiguous set of ligature rules does not need to be ordered in any particular way by the font editor; the implementation software must do the appropriate sorting.

See http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html#5.d

If you are using a different syntax/tool for developing features, then you may need to account for this yourself when writing your feature rules.

If you are asking how they get sorted in the glyph order of the font (for display in a Glyph Palette, for example), then different font editors handle how the glyphs get ordered in a compiled font in different ways. You’d have to check the documentation for your particular software.

Konstantinos Siskakis

Thank you Kent, this is all I was looking for!

Erwin Denissen

Like most other font editors, FontCreator takes care of the order.

Beau Williamson

At least in fontlab, you can switch to index mode and manually change the order of glyphs.