[ft-devel] Make FT_LOAD_TARGET_LIGHT not trigger autohinting for OpenType/CFF fonts?

[Nikolaus Waxweiler]

Hey list,
so I've been discussing some proposed font configuration changes in
#gnome-design on IRC. Someone insisted that my aim of removing all
opinionating about hinting in the layers above fontconfig is misguided
(@Behdad: https://bugs.freedesktop.org/show_bug.cgi?id=11838).

After some back and forth, he found that hintslight translates to
FT_LOAD_TARGET_LIGHT in cairo and argued: FT_LOAD_TARGET_LIGHT always
triggers the autohinter, even when the CFF engine natively does what
LIGHT probably intends to do: Y-only-snapping of stems. That way, GNOME
can be set to default to "slight" so the autohinter handles TrueType and
Type1 fonts and the native CFF engine handles CFF fonts.

Opinions?

What came to my mind:
- Should this also include TrueType fonts once ClearType is fully
handled and the font that should be rendered supports ClearType? What
about emboldening that can't be done on both axes in native mode vs CFF
fonts?
- And by extension, Type1 fonts once the engine is overhauled?
- Once all hinting engines support Y-only-snapping natively, should the
autohinter only activate with the FT_LOAD_FORCE_AUTOHINT flag?