Scrolling is often done on a computer by the CPU or a graphics card. In a WIMP-style graphical user interface, scrolling is done with the help of a scrollbar or using keyboard shortcuts, often the arrow keys. Scrolling is often a key feature in text user interfaces and command line interfaces, though some older computer terminals used a paging mode instead, akin to flipping through a series of pages in a book, usually using the PgUp/PgDn keys or the space bar. computer mice may also have a scroll wheel, which scrolls text vertically when rolled. (Macintoshs have scroll balls that scroll in any direction.) Software such as Adobe Reader can also be scrolled with the hand tool. In this case, the document is dragged and moved around like a piece of paper.
Other PC mouse scrolling is available, although function varies widely between software applications. Some scroll wheels can be pressed down, functioning like a button. Depending on the software, this allows scrolling in both the horizontal and vertical directions by dragging in the direction desired; when the mouse is moved to the original position, scrolling stops. A few scroll wheels can also be tilted, scrolling horizontally in one direction until released.
If any content is too wide to fit on a display, horizontal scrolling is required to view all of it. In applications like graphics and spreadsheets, the content often has a 2D structure, and horizontal scrolling can be useful and necessary.
A web browser normally places as many words in a single line as will fit the width of the browser window. Special HTML-code may instruct the browser to divide the window into columns, in which case it places as many words in a single line as will fit the width of the column.
Scrolling texts, also referred to as scrolltexts or scrollers, were an integral feature of the majority of the demos written for home computers in the 1980s. They were particularly important in crack intros programmed by software crackers, where they were used to convey messages between groups involved in the activity.
Many scrollers were plain horizontal scrollers, but demo coders also paid a lot of attention in finding new and different types of scrolling. The characters could, for example, continuously alter their shape, take unusual flying paths or incorporate color effects such as raster bars.
One of the most famous scrolling texts in movies is the Star Wars opening crawl. The text appears at the bottom of the screen and slowly moves upwards and into the distance as the audience reads it.
Scrolling is commonly used to display the credits at the end of television shows.
In computer and video games, scrolling of a playing field allows the player to control an object in a large contiguous area. Super Bug pioneered this method. Parallax scrolling, which was first featured in Moon Patrol, involves several semi-transparent layers, which scroll on top of each other at varying rates in order to give the illusion of depth.
A previously much used alternative to video game scrolling is the flip-screen method.