VDict mobile



hardware, graphics The most commonly used computer pointingdevice, first introduced by Douglas Engelbart in 1968.
The mouse is a device used to manipulate an on-screen
pointer that's normally shaped like an arrow. With the
mouse in hand, the computer user can select, move, and change
items on the screen.
A conventional roller-ball mouse is slid across the surface
of the desk, often on a mouse mat. As the mouse moves, a
ball set in a depression on the underside of the mouse rolls
accordingly. The ball is also in contact with two small
shafts set at right angles to each other inside the mouse.
The rotating ball turns the shafts, and sensors inside the
mouse measure the shafts' rotation. The distance and
direction information from the sensors is then transmitted to
the computer, usually through a connecting wire - the mouse's
"tail". The computer then moves the mouse pointer on the
screen to follow the movements of the mouse. This may be done
directly by the graphics adaptor, but where it involves the
processor the task should be assigned a high priority to
avoid any perceptible delay.
Some mice are contoured to fit the shape of a person's right
hand, and some come in left-handed versions. Other mice are
symmetrical.
Included on the mouse are usually two or three buttons that
the user may press, or click, to initiate various actions such
as running programs or opening files. The left-most
button (the primary mouse button) is operated with the index
finger to select and activate objects represented on the
screen. Different operating systems and graphical userinterfaces have different conventions for using the other
button(s). Typical operations include calling up a
context-sensitive menu, modifying the selection, or pasting
text. With fewer mouse buttons these require combinations of
mouse and keyboard actions. Between its left and right
buttons, a mouse may also have a wheel that can be used for
scrolling or other special operations defined by the software.
Some systems allow the mouse button assignments to be swapped
round for left-handed users.
Just moving the pointer across the screen with the mouse
typically does nothing (though some CAD systems respond to
patterns of mouse movement with no buttons pressed).
Normally, the pointer is positioned over something on the
screen (an icon or a menu item), and the user then clicks
a mouse button to actually affect the screen display.
The five most common "gestures" performed with the mouse are:
point (to place the pointer over an on-screen item), click
right-click (to press and release the right mouse button},
and drag (to hold down the mouse button while moving the
mouse).
Most modern computers include a mouse as standard equipment.
However, some systems, especially portable laptop and
notebook models, may have a trackball, touchpad or
Trackpoint on or next to the keyboard. These input
devices work like the mouse, but take less space and don't
need a desk.
Many other alternatives to the conventional roller-ball mouse
exist. A tailless mouse, or hamster, transmits its
information with infrared impulses. A foot-controlledmouse is one used on the floor
underneath the desk. An optical mouse uses a
light-emitting diode and photocells instead of a rolling
ball to track its position. Some optical designs may require
a special mouse mat marked with a grid, others, like the
Microsoft IntelliMouse Explorer, work on nearly any surface.
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(1999-07-21)