Border size seems to be off by 1 pixel

[sluukkonen]

Perhaps this is by design, but to my eye, the border rectangle should be one pixel larger.

macOS 11.0.1
yabai 3.3.5

Relevant configuration:

yabai -m config window_border                on
yabai -m config window_border_width          2
yabai -m config active_window_border_color   0xffff0000
yabai -m config normal_window_border_color   0x01000000

[noib3]

I agree, the border seems off in my setup too

[koekeishiya]

This is not a mistake and the border matches the actual window. What you are seeing is the window shadow.

Shadows on:

Shadows off (yabai -m config window_shadow off):

[sluukkonen]

I suppose this makes sense. Thanks!

[sluukkonen]

Hmm. Turning off window shadows seems to remove shadows from everywhere in the UI (e.g. menus, spotlight window and so on).

Would it make sense if the window border was drawn over the shadow when shadows are enabled?

[koekeishiya]

Different windows can have different shadow parameters (at least they used to before Big Sur), so I think that might be tricky to get right. If you look at my pictures above you will notice that the actual wallpaper is shaded also, outside the 1pixel range of the window.