Document how to use filters

[khaledhosny]

I’m trying to use PropagateAnchorsFilter in my UFOs, but I couldn’t find any documentation and had to navigate through the source code (and still navigating).

[anthrotype]

Thanks. Yes, sorry, documentation is none at the moment.

I suggest you have a look at the ufo2ft/filters/__init__.py, especially the loadFilters and getFilterClass functions.

the lib key is "com.github.googlei18n.ufo2ft.filters", contains a plist array of dicts, each dict has a required "name" string (e.g. "Propagate Anchors"), then optional "include" or "exclude" array of strings (glyph names), and depending on the filter class, required positional "args" (plist array) and/or optional "kwargs" (plist dict); finally a "pre" (bool) element to determine whether a filter should happen before (True) or after (False) the default filters.

See the ufo2ft.preProcessor module which manages loading and running the default and custom filters.

[khaledhosny]

Thanks, that is pretty much what I found at the end (then discover that the latest does not have that filter yet 😃).

[anthrotype]

also see https://github.com/googlei18n/glyphsLib/blob/1c9a32266017312e247a432a78e7ed5d85e0c850/tests/builder/builder_test.py#L276-L291

[anthrotype]

I think we can cut a release tomorrow. /cc @moyogo

[khaledhosny]

I’m testing with master now, but I’m not getting my anchors propagated, investigating.

[khaledhosny]

Hmm, looks like fontmake decomposes components before calling ufo2ft compiler, so it is too late for the filter and no anchors gets propagated.

[anthrotype]

Yep. I have a wip branch that makes fontmake use ufo2ft filters for decomposing, removing overlaps and cubic2quadratic conversion. i’ll push soon.