A function in an application that displays exactly how the contents of the current document or window will print so that corrections can be made before the actual printing. In the days of character-based interfaces, a preview was vital to see how fonts and graphics would print. However, with today's applications, a preview mode is still quite useful, especially for Web pages, which often print in an erratic manner. In addition, page breaks become more conspicuous on long documents. See screen capture.