Module window 

frame — the border, corners, shadow and resize edges of a window the system does not decorate.

Window::window_decorations answers which of the two is in force, and it is not a target: GNOME has never implemented xdg-decoration, so a Wayland window there is told Client whatever it asked for, while the same binary under KDE or on X11 is told Server and this draws nothing. macOS and Windows always answer Server.

The window opens transparent or the band shows as a filled rect — WindowBackgroundAppearance::Opaque has the compositor paint the whole surface, corners included.

window::frame(self.content(window, cx), window, cx)

Functions

frame

Wrap a window’s root in the frame it owes.

resize_edge

Which edge a press at pos resizes, or None for a press on the content.