- 
        realization 
      
- 
        See contact realization. 
      
- 
        redirecting control 
      
- 
        Window managers (or client programs) may choose to enforce window
        layout policy in various ways. When a client attempts to change the
        size or position of a window, the operation can be redirected
        to a specified client, rather than the operation actually being
        performed. 
      
- 
        reply 
      
- 
        Information requested by a client program is sent back to the client
        with a reply. Both events and replies are multiplexed on the
        same connection. Most requests do not generate replies. However, some
        requests generate multiple replies. 
      
- 
        representation type 
      
- 
        The type of representation of a resource value. For example, a color
        value might be represented either as a namestring ("red"), a
        pixel value, an RGB triplet, an HSV triplet, and so on. 
      
- 
        request 
      
- 
        A command to the server is called a request. It is a single
        block of data sent over a connection. 
      
- 
        resource 
      
- 
        A value of the user interface that can be changed by the user in a
        resource database via CLX functions
        add-resource,
        get-resource,
        and so forth. See server resource. 
      
- 
        resource class, complete 
      
- 
        See complete resource class. 
      
- 
        resource database 
      
- 
        Conceptually, a set of resource name/value pairs (or resource
        bindings). CLX defines functions for storing and retrieving interface
        resources from a resource database. 
      
- 
        resource name, complete 
      
- 
        See complete resource name. 
      
- 
        RGB values 
      
- 
        Red, green, and blue intensity values used to
        define color. These values are always represented as 16-bit unsigned
        numbers, with zero being the minimum intensity and 65535 being the
        maximum intensity. The values are scaled by the server to match the
        display hardware. 
      
- 
        root 
      
- 
        A special composite contact used to represent an entire display
        screen. 
      
- 
        root window 
      
- 
        Each screen has a root window covering it. It cannot be
        reconfigured or unmapped, but otherwise acts as a full-fledged window.
        A root window has no parent.