set_black_background

Sets whether this GtkGraphicsOffload widget will draw a black background.

A main use case for this is **_letterboxing_** where black bars are visible next to the content if the aspect ratio of the content does not match the dimensions of the monitor.

Using this property for letterboxing instead of CSS allows compositors to show content with maximum efficiency, using direct scanout to avoid extra copies in the compositor.

On Wayland, this is implemented using the single-pixel buffer protocol.

Parameters:

this	a `GtkGraphicsOffload`
value	whether to draw a black background behind the content