Fedora – Font Rendering Change After Upgrade from Fedora 25 to 26

fedorafonts

I did the the Upgrade f25 → f26 and was surprised by a change of the font rendering to the worse. I use the KDE spin and mostly KDE programs but some GTK programs as well.

The following is the change in GVim (GTK) with unchanged settings using “Droid Sans Mono 10” as the editor font. It is enhanced without interpolation to 4× in order to make it easier to spot. Especially the “m” and “g” are affected.

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f25 on the top, f26 on the bottom.

In Konsole (KDE/Qt), a similar regression has happened:

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Other fonts are affected as well, this is Thunderbird (GTK):

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I am not exactly sure what has changed implicitly by the upgrade. It looks like the hinting got worse. How can I get the fonts back to the appearance that I had before?

Update

I have created a file /etc/profile.d/freetype2.sh with contents:

export FREETYPE_PROPERTIES="truetype:interpreter-version=35"

However, this has not changed anything after a full reboot, it still appears in the new version, which I perceive as blurry.

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Best Answer

Freetype 2.7 introduced a new rendering mode and it is used by default (more here https://www.freetype.org/freetype2/docs/subpixel-hinting.html). To revert it add export FREETYPE_PROPERTIES="truetype:interpreter-version=35" to /etc/profile.d/freetype2.sh.

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