r

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.