Re: [ft-devel] Autohinter: stem darkening, first rough prototype

[Nikolaus Waxweiler]

> Emboldening changes the outline but not the metrics or blue zones. It
> is up on you to deal with it. Here is an idea to brush it aside
> gracefully: embolden and scale back. Yes, emboldenig changes the
> bounding box predictably, so that you can restore it by scaling back.
> This will eat away some of your intended emboldening, so use larger
> values to begin with. This should roughly preserve the outer contour
> of the glyph as well as metrics and blue zones.

Clever, and it mostly works (no values change):

http://postimg.org/image/ylk5yy7nn/full/ (no scaling)
http://postimg.org/image/wsh9ammgz/full/ (scaling)

I still spotted one glitch so far, Liberation Sans's "E" has the middle 
horizontal stem snapped 1 pixel to low at various sizes. Maybe a 
rounding problem.

The downside of scaling is, of course, that "i"s are back in the war...

(Code as always in my repo: 
https://github.com/madig/freetype2/tree/stem-darkening-autohinter)