Simplifying access to the Window Server

The Window Server provides a low-level API to the system’s user interface devices — screen, keyboard and pointer. However, the Window Server API provides too much generality for most applications, and one purpose of the UI Control Framework is to simplify the interface by removing some of this generality.

As an example, all Window Server clients must create a Window Server session, active objects, and an active scheduler to receive events from the Window Server. Events received by the client must be channelled to the correct window, and converted into function calls for event handling. This requires complex code which is the same for almost all applications. The control framework therefore implements this within the CCoeEnv class, and control framework applications have only to use the interface provided by CCoeEnv, which is much simpler than using the Window Server API directly.

The framework also maintains objects for accessing the drawing functions, fonts, and resource files which are used by most applications.

Window server.