Window Server Internals: Concepts

This section provides introductory and overview material about the internal workings of the Window Server.

Variant: ScreenPlay and non-ScreenPlay. Target audience: Device creators.

The Window Server Rendering Loop
This topic provides a brief introduction to the Window Server's rendering loop, which takes place in two stages, known as the upper loop and the lower loop.
Redraw Stores
Redraw stores store the sequence of drawing commands representing window contents. Whenever possible, the Window Server performs server-initiated redraws by repeating the sequence of stored commands, rather than by sending redraw requests to the client. This minimises the number of client-server transactions and means that redraws are done as soon as the server detects that they are needed. This topic explains some of the background to redraw stores.