ggiFillscreen - Fill the entire virtual screen
#include <ggi/ggi.h>
int ggiFillscreen(ggi_visual_t vis);
Fills the current clipping rectangle (usually the entire virtual
screen) with the current foreground color. It may be more efficient
than the corresponding call to ggiDrawBox(3). To set a clipping
rectangle, see ggiSetGCClipping(3).
This function returns 0 to indicate success.