Makes sure the given list of rectangles is updated on the given screen\&. The rectangles must all be confined within the screen boundaries (no clipping is done)\&.
This function should not be called while \fBscreen\fR is \fIlocked\fR\&.
.PP
.RS
\fBNote:
.PP
It is adviced to call this function only once per frame, since each call has some processing overhead\&. This is no restriction since you can pass any number of rectangles each time\&.
.PP
The rectangles are not automatically merged or checked for overlap\&. In general, the programmer can use his knowledge about his particular rectangles to merge them in an efficient way, to avoid overdraw\&.