[Development] about the Cocoa/Freetype fontengine

René J. V. Bertin rjvbertin at gmail.com
Mon Jan 1 21:36:06 CET 2018


Nikolaus Waxweiler wrote:


>> All I can say is that I didn't turn it off and that the font smoothing gamma
>> value matters.
> 
> Be more specific.

You asked if gamma correction is enabled in my Qt builds, the only way I can 
answer that without additional information is the way I did. A priori it's 
enabled if it should be by default, not if it should be off by default.

> Last I checked, default X11 builds use a gamma
> correction of 1.0 unless you change the source (only exception, iirc:

The only change I made was the default value of the font smoothing gamma.

> Also see https://bugreports.qt.io/browse/QTBUG-41590 -- I'd love to
> close that one, I'd just need to make stem darkening work well for the

Funny, I never had complaints about too-thin fonts in Qt5 compared to Qt4. 
Certain medium/semibold fonts are indeed thinner (sleeker, not paler), but 
they're too heavy in Qt4.

> Are you sure the preset isn't using the autohinter behind the scenes
> for Ubuntu Mono?

No, I'm not sure and I don't know how to verify that either. But comparing 
specific glyphs with the same font in ftview I'd say that no, autohinting isn't 
on.

There are comments in the tweaked fontconfig files, but they assume a better 
familiarity with the subject than I have.

> The increased x-height at the same point size
> compared to native hinting is very characteristic :)

The at symbol doesn't look like it does when autohinted, in particular.

>> BTW, is there a technical reason to expect one cannot change a
>> fontengine/fontdatabase anymore after the first fonts have been rendered?
> 
> What do you mean?

Basically, can you switch the fontengine and fontdatabase freely at runtime, or 
can this only be done as long as the application hasn't started using fonts?


R.




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