A status bar
, similar to a status line
, is an information area typically found at the bottom of windows
in a graphical user interface
A status bar is sometimes divided into sections, each of which shows different information. Its job is primarily to display information about the current state of its window, although some status bars have extra functionality. For example, many web browsers
have clickable sections that pop up a display of security or privacy information.
A status bar can also be text-based, primarily in console-based applications, in which case it is usually the last row in an 80x25 text mode configuration, leaving the top 24 rows for application data. Usually, the status bar, typically called a status line in this context, displays the current state of the application, plus helpful keyboard shortcuts, such as in the 'vi' text editor of UNIX (from the 1970s) or newer Linux systems.
Status lines have been used for more than 30 years to display advisory messages in a predefined area, rather than as pop-up messages in center screen which can block the view of related information behind the pop-up messages. Although pop-up windows could be used to focus attention, status lines with contrasting hightlighting or colors can also be used to focus attention, without blocking the view.
Sometimes, a video game places the player's vital information (such as hit points, lives, and scoree) on a similar strip across the bottom or top of the screen; this is also referred to as a status bar.
A status bar can be implemented during software development as a component (widget) in a window in a graphical user interface.
An example of a text status line in Emacs
- The status bar of a file manager often shows the count of items in the current directory, their total size, or the size of the currently selected item.
- The status bar of a web browser will sit relatively dormant when the user is viewing on a page, then light up with a flourish of activity when the user clicks a link.
- The status bar of a graphics editor (such as Adobe Photoshop or Microsoft Paint) will show information about the current image, such as its dimensions, colour space, or resolution.
- In a word processor, the status bar often shows cursor position, the number of pages in the document, and the state of the caps lock, num lock, and scroll lock keys. Additionally, many word processors assign the insert key a behaviour similar to that of these three, to allow toggling the insertion mode — the state of that is also displayed in the status bar.
- In a spreadsheet, the status bar shows similar information to word processors, but includes the ability to highlight cells and show the average, sum, maximum value, and so forth.
Status bars allow split-window interface
Status bars, and status lines before them, have been used for years to display advisory messages in a predefined area, rather than as pop-up messages in center screen which can block the view of related information behind the pop-up messages. The use of status bars (or status lines) involves both advantages and disadvantages:
Advantages of status bars:
- status bars allow viewing messages while viewing the total screen;
- status bars allow typing information while viewing status data;
- status bars allow other menu options while viewing status data;
- status bars can continually show status during operation.
Disadvantages of status bars:
- status bars might restrict information to a one-line display (although a variable multi-line status bar/region could be used);
- status bars typically cannot pop to the surface for critical messages.
Although pop-up windows could be used to focus attention, status lines with contrasting hightlighting or colors can also be used to focus attention, without blocking the view.