Scrollbar
Encyclopedia
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
(GUI) with which continuous text, pictures or anything else can be scrolled
Scrolling
In computer graphics, filmmaking, television production, and other kinetic displays, scrolling is sliding text, images or video across a monitor or display. "Scrolling", as such, does not change the layout of the text or pictures, or but incrementally moves the user's view across what is...
including time in video applications, i.e., viewed even if it does not fit into the space in a computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...
, window
Window (computing)
In computing, a window is a visual area containing some kind of user interface. It usually has a rectangular shape that can overlap with the area of other windows...
, or viewport. It was also known as a handle in the very first GUIs.
Scrollbars are present in a wide range of electronic devices including computers, graphing calculators, mobile phones, and portable media players. They usually appear on one or two sides of the viewing area as long rectangular areas containing a bar (or thumb) that can be dragged
Mouse gesture
In computing, a pointing device gesture or mouse gesture is a way of combining pointing device movements and clicks which the software recognizes as a specific command. Pointing device gestures can provide quick access to common functions of a program. They can also be useful for people who have...
along a trough (or track) to move the body of the document as well as two arrows on either end for precise adjustments. The "thumb" has different names in different environments: on the Macintosh
Mac OS X v10.4
Mac OS X v10.4 Tiger is the fifth major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers. Tiger was released to the public on 29 April 2005 for US$129.95 as the successor to Mac OS X Panther , which had been released 18 months earlier...
it is called a "scroller"; on the Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
platform it is called "thumb" or "knob"; Microsoft's .NET documentation refers to it as "scroll box" or "scroll thumb"; in other environments it is called "elevator", "quint", "puck", "wiper" or "grip". Additional functions may be found, such as zooming in/out or various application
Computer software
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....
-specific tools. The thumb can also sometimes be adjusted by dragging its ends. In this case it would adjust both the position and the zooming of the document, where the size of the thumb represents the degree of zooming applied. A thumb that completely fills the trough indicates that the entire document is being viewed, at which point the scrollbar may temporarily become hidden.
A scrollbar should be distinguished from a slider
Slider (computing)
A slider, also known as track bar in Microsoft literature, is an object in a GUI with which a user may set a value by moving an indicator, usually in a horizontal fashion. In some cases the user may also click on a point on the slider to change the setting...
which is another object that works in a similar fashion, the difference being that the slider is used to change values, and does not change the display or move the area that is shown.
Manipulation
While dragging the thumb is historically the traditional way of manipulating a scrollbar, a scroll wheelScroll wheel
A scroll wheel is a hard plastic or rubbery disc on a computer mouse that is perpendicular to the mouse surface. It is normally located between the left and right mouse buttons.- Functionality :...
may also be used. In addition, the arrow buttons may be clicked to scroll a small amount, or the trough above or below the thumb for a larger amount. Sometimes, both arrow buttons appear next to each other for quick, precise manipulation without having to drag the thumb or move the mouse great distances to the other arrow (this was offered as an option in Mac OS 8.5); one of them may also be duplicated so as to show at both ends of the bar, providing familiarity for those used to both separate and adjacent buttons.
Another system for manipulating them is to look at which mouse button was pressed. For instance, a left-click on the down arrow might cause the window to scroll down, while a right click in the same place would scroll up (e.g. RISC OS
RISC OS
RISC OS is a computer operating system originally developed by Acorn Computers Ltd in Cambridge, England for their range of desktop computers, based on their own ARM architecture. First released in 1987, under the name Arthur, the subsequent iteration was renamed as in 1988...
), or the middle button could be used to place the thumb precisely. This form requires less fine motor skills, although it requires a multi-button mouse, and possibly a greater degree of GUI literacy.
Simultaneous 2D-scrolling
Special scroll-bar like widgets allow panning around a two dimensional space by simply moving a single rectangle in any direction on the plane. For example the GtkScrollpane is implemented in the text viewers gv and ghostview.Another example for simultaneous two-dimensional scrolling is an alignment program for protein sequences. Initially, the horizontal scroll-bar looks like a conventional one. But then the scroll-bar offers three additional features:
- It provides an overview of the entire scene.
- The height can be enlarged.
- The knob can not only be moved left and right but also up and down for vertical scrolling.
In RISC OS
RISC OS
RISC OS is a computer operating system originally developed by Acorn Computers Ltd in Cambridge, England for their range of desktop computers, based on their own ARM architecture. First released in 1987, under the name Arthur, the subsequent iteration was renamed as in 1988...
dragging a scrollbar with the left mouse button operates in the usual way, but dragging with the right button causes the pointer to disappear and both scrollbars to be manipulated simultaneously. Many GUI operations in RISC OS perform a related but slightly different function when right clicked.
Customization
The ability and specific methods needed to customize the look and function of scrollbars can vary significantly based on which operating systemOperating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
or software application
Application software
Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...
you are attempting to customize. A common method of altering the look of the scrollbar in Web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...
s is to use CSS
Cascading Style Sheets
Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...
directives to change the scrollbar colors. These are non-standard and supported only by Microsoft Internet Explorer
Internet Explorer
Windows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
versions 5.x or higher.
Another example of customization is the find feature in the Google Chrome
Google Chrome
Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...
browser. It places marks in the trough of the vertical scroll bar to indicate the places where it found the term the user is searching for.
With the invention of new devices such as the tablet pc, there is an increasing need to question the conventional wisdom on where the scroll bar is located. For left hand users, which make a sizeable portion of the population, if the scroll bar is located on the right hand side, the left hand and arm is crossing and blocking the screen.