Display elements are the parts of a window and the display that appear on the system display screen. System metrics are the dimensions of various display elements. Typical system metrics include the window border width, icon height, and so on. System metrics also describe other aspects of the system, such as whether a mouse is installed, double-byte characters are supported, or a debugging version of the operating system is installed. The GetSystemMetrics function retrieves the specified system metric.
Applications can also retrieve and set the color of window elements such as menus, scroll bars, and buttons by using the GetSysColor and SetSysColors functions, respectively.