In computing, WYSIWYG (ˈwɪziwɪɡ ), an acronym for What You See Is What You Get, is a system in which editing software allows content to be edited in a form that resembles its appearance when printed or displayed as a finished product, such as a printed document, web page, or slide presentation. WYSIWYG implies a user interface that allows the user to view something very similar to the result while the document is being created. In general, WYSIWYG implies the ability to directly manipulate the layout of a document without having to type or remember names of layout commands.
Before the adoption of WYSIWYG techniques, text appeared in editors using the system standard typeface and style with little indication of layout (margins, spacing, etc.). Users were required to enter special non-printing control codes (now referred to as markup code tags) to indicate that some text should be in boldface, italics, or a different typeface or size. In this environment there was very little distinction between text editors and word processors.
These applications typically used an arbitrary markup language to define the codes/tags. Each program had its own special way to format a document, and it was a difficult and time-consuming process to change from one word processor to another.
The use of markup tags and codes remains popular today in some applications due to their ability to store complex formatting information. When the tags are made visible in the editor, however, they occupy space in the unformatted text, and as a result can disrupt the desired layout and flow.
Bravo, a document preparation program for the Alto produced at Xerox PARC by Butler Lampson, Charles Simonyi and colleagues in 1974, is generally considered to be the first program to incorporate the WYSIWYG technology, displaying text with formatting (e.g. with justification, fonts, and proportional spacing of characters). The Alto monitor (72 PPI, based on the typographic unit) was designed so that one full page of text could be seen and then printed on the first laser printers.