Page 29 - DCAP504_Computer Graphics

Computer Graphics

• Define resolution
• Explain frame buffer
• Describe logical functioning of I/O devices

Introduction
Computer graphics is a field of computer science that deals with the study of generation of graphic
images, such as line drawings and realistic depiction of natural objects. Production of these images
requires both software and hardware. To generate and display graphic images various special purpose
hardware are used. This unit gives an overview of graphic input and output devices, and the logical
functioning of these devices.
The Input/Output devices play a major role to enable communication between the computer systems
and the external world. Both the input and output devices include certain properties that are required
for computer graphics to function effectively.
A large majority of computer graphics systems utilize some type of Cathode-Ray Tube (CRT) display
and most of the fundamental display concepts are substantiated in CRT display technology. The three
most common types of CRT display technologies are:
1. Direct view storage tube display
2. Calligraphic refresh display
3. Raster scan refresh display
The direct view storage tube display and calligraphic refresh display are line drawing displays, while
the third is a point-plotting device. Few of the displays used in computer graphics are discussed in this
unit.
3.1 Input Devices

An input device refers to hardware devices that are used to send data to the computer. Therefore, we
can say that input devices help in interacting with the computer.
3.1.1 Interactive Devices

The basic function of computer is to accept inputs from the user and process it to obtain the necessary
results, depending on a sequence of instructions. According to computer terminology, devices that are
capable of providing input and receiving output to and from the computer are known as hardware. An
input device receives information from the user and translates it into a computer understandable
language. That is, into a language that the CPU can understand. The information is processed in the
CPU and the output is transferred to the output device in a user understandable language.

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