Mouse play a very important role in development of Computer Graphics and to implement graphics in the computer system. Mouse is a pointing input device that points out item(s) by cursor. The cursor can be move from one position to another, this movement of cursor is due to the movement of mouse in the plane surface. The movement of mouse occurs only in two directions- vertical and horizontal. Mouse always measures its relative movement from its last position.
Commonly two types of mice are used in Computer system- a. Normal Mouse and b. Optical Mouse
Normal Mouse: consists of one mouse ball which adjust in such a way that it rotates in both direction with respect to the movement of mouse in plane surface. The mouse ball is attached with two rollers- one vertical and another horizontal. There are also two sensors which sense movement of mouse or rotation of roller and converts this information to digital value by potentiometer and sens to the computer hence changing the position of cursor.
Optical Mouse: works in a different principle than the normal mouse. Optical mouse functions according to the reflection of light. Optical mouse have light emitting device. According to the movement of mouse, the direction of reflection of light from the surface changes. Light sensor senses the direction- both horizontal and vertical, and sends to the computer after encoding.
Both sorts of mouse consists of two or three buttons to send command to computer to perform the operations such as click, right click, to open menus etc. The main operations perform by mouse are select, drag, open etc.