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Unformatted text preview: d to create
graphic elements on the screen, such as lines, curves, and freehand shapes. With this new
ability, these devices came to be known as point-and-draw devices. These input devices
have made computers a much easily usable tool and have also established the computer
as a versatile tool for graphic designers. Some of the most commonly used point-anddraw devices are described below.
As of today, the mouse is the most popular point-and-draw device. It has become a musthave input device on personal computers and workstations that have a GUI-based video
display terminal. As shown in Figure 9.4, the mouse is a small hand-held device, which
can comfortably fit in a user's palm. It rolls on a small bearing and has one or more
buttons on the top. When a user rolls the mouse across a flat surface, such as on top of the
table on which the computer is placed, the graphics cursor moves on the screen of the
video display terminal in the direction of the mouse's movement. The graphics cursor,
which is used to point and draw, is displayed on the screen as a variety of symbols such
as an arrow ( fl ), a wrist with a pointing finger (m~), etc. Depending on the application,
the text and graphics cursor may be displayed on the screen at the same time. Since all movements of the mouse are reproduced by the graphics cursor on the screen,
you can move the graphics cursor at a menu item or an icon by moving the mouse. For
example, move the mouse away from you to move the cursor up on the screen, move the
mouse towards you to move the cursor down on the screen, move the mouse right to
move the cursor right on the screen, and move the mouse left to move the cursor left on
the screen. In this way, the mouse can be used for quick positioning of the graphics
cursor on the desired menu item or an icon. When positioned at a menu item or an icon,
the graphics cursor is said to point to that menu item or icon. With a click of the mouse's
button, the system can then be notified of this choic...
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This document was uploaded on 04/07/2014.
- Spring '14