15.34. Glossary¶

icon: A small picture that represents some functionality in a computer program. A user clicks on an icon to cause an action to be performed by a program.
widget: A visual element of a graphical user interface that allows a user to give commands to an executing program. Example widgets include a command button, a slider bar, or a list box.
graphical user interface: A user interacts with a computer program by pointing, clicking, and dragging icons and widgets in a window on a computer screen.
GUI: An abbreviation for a “graphical user interface.”
event-driven programming: A program that only executes tasks when a user specially requests a task.
event loop: A built-in function of a GUI toolkit that “listens” for operating system events and then calls an appropriate event-handler for each event.
event-handler: A function that processes an event. These functions are also called callback functions.