Re: [ft-devel] Taming CFF_CONFIG_OPTION_DARKENING_PARAMETER_Y* for a gamma of ~2.2/sRGB?

[Dave Arnold]

Hi Dave,

On 8/25/2015 8:53 PM, Dave Crossland wrote:
> > As you noted, stdHW and stdVW are normally obtained from a CFF font 
> dictionary. For TT, we (at Adobe) estimate stem width values based on the OS/2 
> weight class. We use three values, light (50/1000), regular (75/1000) and bold 
> (110/1000).
>
> I'm confused about this. If a single style family had a weight class of 400 but 
> it's stems are much more/less than 75, will that font be darkened/lightened too 
> much?
Yes, you are correct. The heuristic I described was a compromise for a mobile 
rasterizer that needed to be small and simple. In a more complete Adobe 
rasterizer, we analyse the outlines to get a more accurate stem width value. I 
think the autohint code may have the necessary information to do this, too.

Thanks.

-Dave