Function tinted_buffer 

pub(crate) fn tinted_buffer(
    shm: &WlShm,
    handle: &QueueHandle<Probe>,
    width: i32,
    height: i32,
    pixel: [u8; 4],
) -> WlBuffer

The same, in a colour of the caller’s choosing.

Worth the parameter because the whole point of some of these checks is telling whose pixels are on screen: the lock screen has to be a colour nothing else in the compositor draws, or a screenshot proves nothing.