Glyphs using a single shape overlapping itself failed to be flattened

[newforms]

Overlaps aren't removed in glyphs using a single shape, overlapping itself (i.e. "P", "e", "6", "9", etc.).

[rsms]

The bug is in fontbuild at

inter/misc/pylib/fontbuild/Build.pyx

Lines 307 to 310 in f7868ac

	if len(contours) > 1:
	manager = BooleanOperationManager()
	glyph.clearContours()
	manager.union(contours, glyph.getPointPen())

An optimization looks at a glyph's contours and if there's only a single contour—as the case with e.g. "e"—it skips the expensive union boolean operation. There's probably a cheap way to check if there's any overlap even for single-contour glyphs.

[rsms]

I have a fix for this, but it increases build times by a considerable amount of time (29s -> 43s). Before pushing a fix for this, I want to investigate if I can speed up the process.

[rsms]

I wasn't able to find a way to speed things up, so considering 57238c6 to fix this.

[rsms]

Here's a build with the fix
Inter-UI-2.5-57238c6c82.zip

[rsms]

Beta release with these changes incorporated: https://github.com/rsms/inter/releases/tag/v2.5-beta

[newforms]

Thank you!