[ft-devel] How to determine if horizontal hinting is happening?

[Adam Goode]

Hi,

I am working on a Chrome bug (crbug.com/740385) related to subpixel positioning and hinting.

There is currently an issue where glyphs do not get positioned correctly in all cases, and to solve this problem I need to enable subpixel positioning.

This works, except when horizontal hinting is enabled ("full hinting" in xft enables this). In this case, letters get smeared badly.

https://www.freetype.org/freetype2/docs/glyphs/glyphs-3.html suggests that I should do subpixel positioning if I am not hinting horizontally, which matches with my understanding.

Therefore, I would like to programatically determine if horizontal hinting is happening and base the subpixel positioning decision on this information. But I have not been able to figure out how to do this. Is there a way that avoids needing to know the internals of the engines?

Thanks,

Adam