Hi,
On Windows, Gtk will by default use
- the platform’s font renderer (i.e. DirectWrite or GDI)
- the system font (i.e. “Segoe UI 9”)
But due to technical reasons, Gtk4 doesn’t support RGB subpixel aliasing, but only grayscale. This is an issue, because:
- DirectWrite doesn’t handle grayscale subpixels as good as RGB ones
- The Segoe font is optimized for RGB aliasing, and renders weird in grayscale
There are several options to improve rendering:
- disable DirectWrite in Pango, like they do in msys2 (see patches)
- use another font renderer, like fontconfig, by setting the environment variable
PANGOCAIRO_BACKEND=fc
- use another font than Segoe
I detailed some days ago my personal font config on Windows, you may want to have a look.