How the background behaves, mirroring the background-mode GSettings key.
Mirror and spanned resolve identically and differ only in how the renderer
paints the result.
Members
CINNAMON_BG_MODE_INDEPENDENT
Each monitor is matched to its own entry, so
monitors can show different backgrounds.
CINNAMON_BG_MODE_MIRROR
A single connector-less entry, shown on every
monitor.
CINNAMON_BG_MODE_SPANNED
A single entry, painted as one image across all
monitors.