Change default verticalOrigin from glyph height to hhea.ascender?

[mashabow]

When verticalOrigin is not set, OutlineCompiler currently uses the glyph height as a fallback value:

https://github.com/googlei18n/ufo2ft/blob/ed1c03804bfedb2cba621c61652dee6dece43ac8/Lib/ufo2ft/outlineCompiler.py#L38-L45

However, it seems more reasonable to use hhea.ascender than the glyph height. This is a very common setting especially in CJK fonts.

[behdad]

Ascender sounds wrong. I would have expected either ascender+descender. No?

[moyogo]

The height would be ascender+abs(descender), but for the vertical origin taking the ascender as a fallback makes sense.

[behdad]

Right. My bad. Was thinking about vertical advance.