Scrolling

From Free net encyclopedia

In computer graphics and television, scrolling or text crawling is the act of sliding a horizontal or vertical presentation of content, such as text, drawings, or images, across a screen or display window. Scrolling is often used to show reams of data longer than the viewport. The word scroll is derived from the way in which people read scrolls of paper, by rolling up the top of the page and allowing objects lower on the page to move up.

Computing

On a computer, scrolling may be performed by software running on a computer's CPU, or it may be done by performing some operation on a dedicated 2D computer graphics chip. At the 1980s home computer demo scene, and in the era's computer and video games, scrolling was often an integral feature.

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. Modern computer mice may also have a scroll wheel.

If any content is too wide to fit on a display, horizontal scrolling is often required to view all of it. This is often considered impractical and annoying, as the user must scroll back and forth in two dimensions, instead of just up and down. Such a problem is very common on certain websites; one exception to this rule is spreadsheets, as they are arranged in a fashion that makes this less of a problem. On the other hand, vertical scrolling is very common, as it only requires movement in a single dimension.

Television

Scrolling is commonly used to display the credits at the end of television shows.

Scrolling is also used in television news when a news ticker is employed, scrolling news stories horizontally across the bottom of the screen.

Video games

In 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.fr:Scrolling fi:Näytön vieritys