On some systems, to_node -> render_texture generates empty or garbled
textures since GTK 4.18 GNOME/gtk#7464. This does not happen when using the cairo
renderer.
Closes#488
`GdkSurface:scale` supports fractional scaling available as
"scale-monitor-framebuffer" on Mutter. Use this value everywhere
instead of the integer scale-factor
Closing #182