In working with associate designers, using UFO as a transfer format between FontLab and Glyphs, we’ve noticed that Glyphs incorrectly positions some components. This seems to happen mostly when a composite glyph does not inherit the metrics of the first component, e.g. Greek uppercase diacritics, digraphs, precomposed fractions, but I’ve also seen it affect Vietnamese diacritics where the composite does inherit metrics from the base letter.
This is how a set of precomposed fractions composite glyphs looked in FontLab VI (also FLS5):
When I export a UFO from FLVI (or create one using vfb2ufo from a FLS5 source; I’ve tested both methods), and then open the UFO I get this:
If I open the same UFO in FLVI, the composites are fine. I’ve also checked the XML for these glyphs in the UFO folder, and the offsets are correctly recorded:
<?xml version="1.0" encoding="UTF-8"?> <glyph name="onequarter" format="1"> <advance width="1446"/> <unicode hex="00BC"/> <outline> <component base="onesuperior" yOffset="39"/> <component base="fraction" xOffset="522"/> <component base="foursuperior" xOffset="752" yOffset="-619"/> </outline> <lib> <dict> <key>com.typemytype.robofont.mark</key> <array> <real>0.713</real> <real>0.6</real> <real>1</real> <real>1</real> </array> </dict> </lib> </glyph>
So it does seem like Glyphs is at fault here.