Setting USE_MY_METRICS (0x0200) the way ufo2ft does (to the component whose base glyph has the same advance width and horizontal positioning as the composite glyph as a whole) is not necessary for fonts that do not have hinted metrics
Having this flag set doesn't hurt either (it's basically no-op for unhinted fonts), thus I don't want to change the default behavior otherwise it will produce spurious diffs.
At least we allow to disable this feature. It will also help us when comparing the output of fontmake-py vs fontmake-rs (which does not implement this unnecessary USE_MY_METRICS flag setting).
Setting USE_MY_METRICS (0x0200) the way ufo2ft does (to the component whose base glyph has the same advance width and horizontal positioning as the composite glyph as a whole) is not necessary for fonts that do not have hinted metrics Having this flag set doesn't hurt either (it's basically no-op for unhinted fonts), thus I don't want to change the default behavior otherwise it will produce spurious diffs. At least we allow to disable this feature. It will also help us when comparing the output of fontmake-py vs fontmake-rs (which does not implement this unnecessary USE_MY_METRICS flag setting).
(FWIW Glyphs.app also does not set this flag)