Features of Graphical Interfaces

Basic Features of Graphical Interfaces
Graphical systems use windows to display information and thus allow more than one window to be displayed at any time. Each window is associated with a running program. User input is derived from a keyboard and mouse.
The mouse
The mouse, invented in 1963 at the Stanford Research Institute by Douglas Engelbart, has done much to enhance the use of the personal computer. Engelbart's prototype, made of wood, with metal disks for rollers that detected the motion of the mouse, was further developed by Xerox at it's Palo Alto Research Center in the early 1970's under the direction of Jack S Hawley.

Most mice have two or more buttons, which users depress to select items from a menu or click on graphical objects on the computer screen, thus sending commands to the computer.

The mouse is held in the hand and moved across a flat surface. As the mouse is moved, its movement is detected and translated into both X and Y movements, which updates the indicated position of the mouse pointer on the computer screen accordingly.

The mouse cursor
The position of the mouse is shown on the screen as the mouse cursor and is denoted by a number of symbols.

	Standard mouse pointer
	Indicates computer is busy

Selecting items with the Mouse
Single Click
A single mouse click refers to moving the mouse pointer over the desired item and quickly pressing the left mouse button once.
Double Click
A double mouse click refers to moving the mouse pointer over the desired item and quickly pressing the left mouse button twice in rapid succession.
Drag
A drag or move operation is performed by moving the mouse pointer over the desired item and holding the left mouse button down. The mouse is then used to move to drag the object or window to the new position, then the left mouse button is released.