fn require_32bpp(conn: &RustConnection, screen: usize) -> Result<(), String>Expand description
Reject a server whose root visual is not 32 bits per pixel.
Every ShmSurface is sized at width * 4 bytes per row and the capture is read as packed
BGRA, so a root of any other depth would be grabbed as garbage rather than failing. Checked
on the initial connection and again on every reconnect, since a restarted server can come
back with a different visual.