Font antialiasing issue on GTK in MacOS

Platform
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1

Below is the screenshot from gtk4-demo (4.18.3) built from jhbuild modulesets-unstable/gtk-osx.modules on MacOS 12.x (Monterey).

Font_Issue_MacOS_Monterey
Font_Issue_MacOS_Monterey1024×768 98.3 KB

The text font doesn’t look great. GTK inspector shows coretext for Pango Fontmap.

Font_Issue_MacOS_Monterey-2
Font_Issue_MacOS_Monterey-21024×768 85.4 KB

On my Debian Unstable, GTK inspector shows fontconfig for Pango Fontmap as below.

Font_Issue_MacOS_Monterey-3
Font_Issue_MacOS_Monterey-31025×711 99.4 KB

I guess I’ve built Pango, Cairo with fontconfig (as I haven’t changed the deps in .modules for Pango / Cairo).

Ideas?

2

Yes, Pango defaults to CoreText on macOS. If you wish to use FontConfig + FreeType2, set the environment variable PANGOCAIRO_BACKEND=fc

1 Like
3

set the environment variable PANGOCAIRO_BACKEND=fc

That works. Any reason why it’s not the default on macOS.

Screenshot with font scaling set to 1.1.

Font_Issue_Fixed_MacOS_Monterey
Font_Issue_Fixed_MacOS_Monterey1024×768 106 KB

4

Point being text in GTK apps should look good:

  • the GNOME way (fontconfig etc) -or-
  • macOS way (for native look and feel).

But the text in GTK demo app looks quite different from other native macOS apps.

FWIW, GTK Inspector shows the selected font as .AppleSystemUIFont when using coretext backend.