From Wikipedia, the free encyclopedia
In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input.
In most command line interfaces, the cursor is an underscore or solid rectangle, which may be flashing or steady, indicating where text will be placed when entered. For example, a typical MS-DOS prompt appears as:
Some interfaces use an underscore or thin vertical bar to indicate that the user is in insert mode, where text will be inserted in the middle of the existing text, and a larger block to indicate that the user is in overtype mode, where inserted text will overwrite existing text.
Interfaces driven by a computer mouse or other pointing device add a second cursor to show the current position of the mouse pointer. In text user interfaces, such as early versions of Microsoft Windows, this cursor is frequently a solid rectangle; depending on the interface, the rectangle may always be a single color, or may be the opposite color of whatever lies "below" it. Graphical user interfaces usually use an arrow-like pointer to show the mouse position, and a solid line as a text insertion point. (Some users refer to the insertion-point cursor as a caret to distinguish it from the mouse cursor; others use the terms mouse pointer and text cursor to likewise disambiguate.) The blinking of the text cursor is usually temporarily suspended when it is being moved; otherwise, the cursor may change position when it is not visible, making its location difficult to follow. Many TUIs and GUIs give the user the option to turn off the mouse cursor when text is being typed.
In many GUIs, the mouse cursor changes shape depending on the circumstances. For example:
- In text that the user can select or edit, the cursor changes to a vertical bar with little cross-bars (or curved serif-like extensions) at the top and bottom - sometimes called an "I-beam" since it resembles the cross-section of the construction detail of the same name.
- When displaying a document, the cursor can appear as a hand with all fingers extended allowing scrolling by "pushing" the displayed page around.
- Graphics-editing cursors such as brushes, pencils or paint buckets may display when the user edits an image.
- On an edge or corner of a window the cursor usually changes into a double arrow (horizontal, vertical, or diagonal) indicating that the user can drag the edge/corner in an indicated direction in order to adjust the shape of the window.
- While a computer process is performing tasks and cannot accept user input, a wait cursor (an hourglass in Windows and many other systems, watch in classic Mac OS, or spinning ball in Mac OS X) is displayed when the mouse cursor is in the corresponding window.
- When the cursor hovers over a hyperlink, it changes into a hand with an outstretched index finger. Often some informative text about the link may pop up in a tooltip, which disappears when the user moves the cursor away. The tooltips revealed in the box depend on the implementation of the web browser; many web browsers will display the "title" of the element, the "alt" attribute, or the non-standard "tooltips" attribute. This cursor shape was first used for hyperlinks in Apple Computer's HyperCard.
- Susan Kare, designer of several of the common cursor shapes