Editing Scrolling

{{Short description|Sliding motion vertically or horizontally over display devices}}
{{Other uses|Scroll (disambiguation)}}
{{Wiktionary}}
[[File:Parallax scrolling example scene.gif|thumb|[[Parallax scrolling]]]]
In [[computer display]]s, [[filmmaking]], [[television production]], [[video games]] and other kinetic displays, '''scrolling''' is sliding text, images or video across a monitor or display, vertically or horizontally. "Scrolling," as such, does not change the layout of the text or pictures but moves ([[panning (camera)|pans]] or [[Tilt (camera)|tilts]]) the user's view across what is apparently a larger image that is not wholly seen.<ref>{{Cite web|url=https://www.encyclopedia.com/science-and-technology/computers-and-electrical-engineering/computers-and-computing/scroll|title=Scroll|date=2009|website=Encyclopedia.com|access-date=23 February 2019}}</ref> A common television and movie special effect is to scroll credits, while leaving the background stationary. Scrolling may take place completely without user intervention (as in film credits) or, on an interactive device, be triggered by [[touchscreen]] or a keypress and continue without further intervention until a further user action, or be entirely controlled by [[input device]]s.

Scrolling may take place in discrete increments (perhaps one or a few lines of text at a time), or continuously ('''smooth scrolling'''). [[Frame rate]] is the speed at which an entire image is redisplayed. It is related to scrolling in that changes to text and image position can only happen as often as the image can be redisplayed. When frame rate is a limiting factor, one smooth scrolling technique is to blur images during movement that would otherwise appear to "jump".

==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>

==Film and television==
Scrolling is commonly used to display the credits at the end of [[film]]s and [[television program]]s.

Scrolling is often used in the form of a [[news ticker]] towards the bottom of the picture for content such as [[television news]], scrolling sideways across the screen, delivering short-form content.

== Video games ==<!-- This section is linked from [[Bubble Bobble]] -->
{{see also|Side-scrolling video game|Vertically scrolling video game|Parallax scrolling|2.5D}}

In [[Video game|computer and video games]], scrolling of a playing field allows the player to control an object in a large contiguous area. Early examples of this method include [[Taito]]'s 1974 vertical-scrolling [[racing video game]] ''[[Speed Race]]'',<ref>{{KLOV game|id=9709|name=Speed Race}}</ref> [[Sega]]'s 1976 [[2.5D|forward-scrolling]] [[racing game]]s ''[[Fonz (arcade)|Moto-Cross]]''<ref name=Moto-Cross>{{KLOV game|12812|Moto-Cross}}</ref> (''Fonz'')<ref name=Fonz>{{KLOV game|id=12812|name=Fonz}}</ref> and ''Road Race'',<ref name=Road-Race>{{KLOV game|12733|Road Race}}</ref> and ''Super Bug''. Previously the [[flip-screen]] method was used to indicate moving backgrounds.

The [[Namco Galaxian]] [[arcade system board]] introduced with ''[[Galaxian]]'' in 1979 pioneered a [[Sprite (computer graphics)|sprite]] system that animated pre-loaded sprites over a scrolling background, which became the basis for [[Nintendo]]'s ''[[Radar Scope]]'' and ''[[Donkey Kong (arcade game)|Donkey Kong]]'' arcade hardware and [[home console]]s such as the [[Nintendo Entertainment System]].<ref>[https://web.archive.org/web/20120505103737/http://www.glitterberri.com/developer-interviews/how-the-famicom-was-born/making-the-famicom-a-reality/ Making the Famicom a Reality], ''Nikkei Electronics'' (September 12, 1994)</ref>

[[Parallax scroll]]ing, which was first featured in ''[[Moon Patrol]]'', involves several [[transparency (optics)|semi-transparent]] layers (called playfields), which scroll on top of each other at varying rates in order to give an early [[2.5D|pseudo-3D]] illusion of depth.<ref>{{cite web|url=http://www.gamesradar.com/f/gamings-most-important-evolutions/a-20101008102331322035/p-3|title=Gaming's Most Important Evolutions|page=3|publisher=[[GamesRadar]]|date=October 8, 2010|access-date=2011-04-27}}</ref>

'''{{vanchor|Belt scrolling}}''' is a method used in side-scrolling [[beat 'em up]] games with a downward camera angle where players can move up and down in addition to left and right.

== Studies ==
A 1993 article by George Fitzmaurice studied spatially aware [[palmtop computer]]s. These devices had a 3D sensor, and moving the device caused the contents to move as if the contents were fixed in place. This interaction could be referred to as “moving to scroll.” Also, if the user moved the device away from their body, they would zoom in; conversely, the device would zoom out if the user pulled the device closer to them. [[Smartphone]] [[camera]]s and “[[optical flow]]” image analysis utilize this technique nowadays.<ref>{{Cite journal|last=Fitzmaurice|first=George W.|date=1993-07-01|title=Situated Information Spaces and Spatially Aware Palmtop Computers|journal=Commun. ACM|volume=36|issue=7|pages=39–49|doi=10.1145/159544.159566|s2cid=16997188|issn=0001-0782|doi-access=free}}</ref>

A 1996 research paper by [[Jun Rekimoto]] analyzed tilting operations as scrolling techniques on small screen interfaces. Users could not only tilt to scroll, but also tilt to select menu items. These techniques proved especially useful for field workers, since they only needed to hold and control the device with one hand.<ref>{{Cite book|last=Rekimoto|first=Jun|chapter=Tilting operations for small screen interfaces |title=Proceedings of the 9th annual ACM symposium on User interface software and technology - UIST '96|date=1996-01-01|location=New York, NY, USA|publisher=ACM|pages=167–168|doi=10.1145/237091.237115|isbn=978-0897917988|citeseerx=10.1.1.19.8330|s2cid=15104495}}</ref>

A study from 2013 by Selina Sharmin, Oleg Špakov, and Kari-Jouko Räihä explored the action of reading text on a screen while the text auto-scrolls based on the user's [[eye tracking]] patterns. The control group simply read text on a screen and manually scrolled. The study found that participants preferred to read primarily at the top of the screen, so the screen scrolled down whenever participants’ eyes began to look toward the bottom of the screen. This auto-scrolling caused no statistically significant difference in reading speed or performance.<ref>{{Cite book|last1=Sharmin|first1=Selina|last2=Špakov|first2=Oleg|last3=Räihä|first3=Kari-Jouko|title=Proceedings of the 2013 Conference on Eye Tracking South Africa |chapter=Reading on-screen text with gaze-based auto-scrolling |date=2013-01-01|series=ETSA '13|location=New York, NY, USA|publisher=ACM|pages=24–31|doi=10.1145/2509315.2509319|isbn=9781450321105|s2cid=18759763}}</ref>

A undated study occurring during or after 2010 by Dede Frederick, James Mohler, Mihaela Vorvoreanu, and Ronald Glotzbach noted that parallax scrolling "may cause certain people to experience nausea."<ref>{{Cite journal|last=Frederick|first=Dede|title=The Effects of Parallax Scrolling on User Experience in Web Design|journal=Journal of User Experience|volume=10|issue=2}}</ref>

==See also==
{{Commons category|Scrolling}}
* [[Flip page]]{{snd}}an alternate visual effect for navigating digital publications

==Notes==
{{reflist|group=notes}}

==References==
{{reflist|35em}}

[[Category:Television technology]]
[[Category:Video game design]]
[[Category:Computer graphics]]
[[Category:Demo effects]]
[[Category:User interface techniques]]