Re: Hinting regression in Ubuntu 23.04

[Werner LEMBERG]

>> This is B/W monochrome rendering with full hinting.  As can be
>> seen, the result is just fine.  I'm quite confident that the
>> problem is *not* with FreeType.
> 
> This is a regression from 22.10 to 23.04 and Ubuntu(-mono) has seen
> some changes since 22.10, so let's compare the same font, because I
> do suspect weird (libfreetype?) behaviour on Ubuntu 23.04 which I
> can't explain.
> 
> Attached is a screenshot of OpenSans-VariableFont_wdth,wght.ttf
> using the same commandline.

Well, all variation fonts I'm aware of have *zero* TrueType hints for
B/W rendering!  In case you are using Ubuntu VF (I've seen the demo on
https://design.ubuntu.com/font but didn't find the place where to
download it), I'm very confident that the same is true for this font.
In other words, if you want good B/W rendering of the Ubuntu font,
don't use the VF incarnation of it.

> Attached is a screenshot of OpenSans-VariableFont_wdth,wght.ttf
> using the same commandline. It clearly shows bad hinting and I'm
> convinced this looked better hinted on 22.04 [...]

I think you misremember, for the reason mentioned above – just to be
sure I've checked now that this variation font has no B/W hinting
instructions.  Its hinting was certainly equally bad with an older
version of FreeType.

You might try to enforce auto-hinting in B/W mode, which should
improve things slightly.  However, be warned that the results are
*far* from good in many cases; we actually don't support auto-hinting
in B/W mode.


    Werner