Editing Scrolling (section)

==Computing==

=== Implementation ===
{{anchor|software scrolling|hardware scrolling}}
Scrolling is often carried out on a computer by the CPU (''software scrolling'') or by a [[graphics processor]]. Some systems feature ''hardware scrolling'', where an image may be offset as it is displayed, without any [[frame buffer]] manipulation (see also [[hardware windowing]]). This was especially common in 8 and 16bit video game consoles.

=== UI paradigms ===
In a [[WIMP (computing)|WIMP]]-style [[graphical user interface]] (GUI), user-controlled scrolling is carried out by manipulating a [[scrollbar]] with a mouse, or using [[keyboard shortcut]]s, often the [[arrow key]]s. Scrolling is often supported by [[text user interface]]s and [[command line interface]]s. Older [[computer terminal]]s changed the entire contents of the display one screenful ("page") at a time; this paging mode requires fewer resources than scrolling. Scrolling displays often also support page mode. Typically certain keys or [[key combination]]s page up or down; on [[PC-compatible]] keyboards the [[page up and page down keys]] or the [[space bar]] are used; earlier computers often used [[control key]] combinations.<ref group="notes">The widely used [[Wordstar]] word processor used the "diamond" of Ctrl-S/E/D/X to move the cursor left, up, right, and down, and Ctrl-R and Ctrl-C to page up and down.</ref> Some [[Computer mouse|computer mice]] have a [[scroll wheel]], which scrolls the display, often vertically, when rolled; others have [[scroll ball]]s or [[tilt wheel]]s which allow both vertical and horizontal scrolling.

Some software supports other ways of scrolling. [[Adobe Reader]] has a mode identified by a small hand icon ("[[hand tool]]") on the document, which can then be dragged by clicking on it and moving the mouse as if sliding a large sheet of paper. When this feature is implemented on a [[touchscreen]] it is called ''kinetic scrolling''. [[Touchscreen|Touch-screens]] often use ''inertial scrolling'', in which the scrolling motion of an object continues in a decaying fashion after release of the touch, simulating the appearance of an object with [[inertia]]. An early implementation of such behavior was in the "Star7" [[Personal digital assistant|PDA]] of [[Sun Microsystems]] ca. 1991&ndash;1992.<ref>{{cite web|url=https://www.youtube.com/watch?v=1CsTH9S79qI&t=4m28s|title=Star7 Demo|last=JamesAGosling|date=19 October 2007 |access-date=8 February 2019|via=YouTube}}</ref>

Scrolling can be controlled in other software-dependent ways by a PC mouse. Some scroll wheels can be pressed down, functioning like a button.  Depending on the software, this allows both horizontal and vertical scrolling 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. On [[touchscreen]] devices, scrolling is a [[multi-touch]] gesture, done by swiping a finger on the screen vertically in the direction opposite to where the user wants to scroll to.

If any content is too wide to fit on a display, horizontal scrolling is required to view all of it. In applications such as [[graphics]] and [[spreadsheet]]s there is often more content than can fit either the width or the height of the screen at a comfortable scale, and scrolling in both directions is necessary.

===Infinite scrolling===
{{main|Infinite scrolling}}
{{see also|Doomscrolling}}

In contrast to [[Pagination|material divided into discrete pages]], the web design approach of [[infinite scrolling]] dynamically adds new material to the user display, leading to a continuous, apparently bottomless or endless scrolling experience.

===Text===
In [[Horizontal and vertical writing in East Asian scripts|languages written horizontally]], such as most Western languages, text documents longer than will fit on the screen are often displayed [[Word wrap|wrapped]] and sized to fit the screen width, and scrolled vertically to bring desired content into view. It is possible to display lines too long to fit the display without wrapping, scrolling horizontally to view each entire line. However, this requires inconvenient constant line-by-line scrolling, while vertical scrolling is only needed after reading a full screenful.

Software such as [[word processor]]s and [[web browser]]s normally uses word-wrapping to display as many words in a single line as will fit the width of the screen or window or, for text organised in columns, each column.

===Demos===
Scrolling texts, also referred to as ''scrolltexts'' or ''scrollers'', played an important part in the birth of the computer [[Demo (computer programming)|demo culture]]. The [[Software cracking|software cracker]]s often used their deep knowledge of [[computer platform]]s to transform the information that accompanied their releases into [[crack intro]]s. The sole role of these intros was to scroll the text on the screen in an impressive way.<ref>{{cite web |url=http://tomaes.32x.de/text/faq.php#2.3 |title=PC Demoscene FAQ |website=tomaes.32x.de |access-date=6 June 2022 |archive-url=https://web.archive.org/web/20031209225520/http://tomaes.32x.de/text/faq.php#2.3 |archive-date=9 December 2003 |url-status=dead}}</ref>