Computer Graphics: Introduction

• Computers have been a core part of efficient and economical image generation and manipulation. Advancement in computer technology has made graphics processing faster and more economical.
• Today, the scope of the term computer graphics is not limited to what kind of scene can be displayed or what kind of images we can generate with the help of a computer. In broad mean, computer graphics has covered almost every and every field, like education, animation, entertainment, film industry, fine arts, gaming, engineering, training, advertisement, medicine, statistical representation and many more.
• Computer graphics is a process of generating, manipulating, storing and displaying images. Computer graphics has made things more easy and interesting.

• A person is more interested in studying monthly or annual statistics in the form of graphs, tables or charts, instead of plain boring textual data.
• It is the key component for presentation and user interface. Old slow and time-consuming command line interfaces have been replaced by quick, fascinating Graphical User Interface (GUI). GUI provides a quick and easy-to-use interface to the application users.
• Due to inefficient and expensive hardware, before a couple of decades, application areas of computer graphics were limited. But with the evolution of digital systems and personal computers, there is a flood of inexpensive graphics-based applications and devices.
• With the help of GUI, multiple users can control simultaneous applications like text editors, code editors, entertainment tools etc. very easily. Computer graphics was initially started by displaying data on hard copy display devices like plotters, printers and then Cathode Ray Tube (CRT). Today, the applications of computer graphics have been extended to display devices like Light Emitting Diodes (LED), Liquid Crystal Display (LCD), electroluminescent displays, flat CRTs etc.
• Computer graphics perform various operations on objects like translation, rotation, scaling, reflection, shearing, hidden surface removal, texture mapping, shading etc. to generate a realistic scene.

Operations:

Operations of computer graphics can be classified as follows :

• Geometry : How to draw and represent the scene.
• Animation : How to add dynamic content to the scene.
• Rendering : How to add realistic light to the scene.
• Imaging : Image acquisition and image editing.

Classification:

Based on user interaction and user control, computer graphics can be classified into main two categories :

Passive Computer Graphics: It is also known as offline computer graphics or non-interactive computer graphics. In passive computer graphics, the user has no control over the displayed scene. It means the user can’t make any changes to the scene shown on the screen. Content of static websites, and logos displayed on television channels are examples of passive computer graphics. This type of graphics provides only one-way communication. The graphic does not do anything special when the user tries to interact with it.

Active Computer Graphics: It is also known as online computer graphics or interactive computer graphics. It is dynamic in nature and provides two-way communication. Displays are controlled by input devices like mouse, keyboard etc. The graphics respond to what the user does to it. It may change the color of the area clicked by the user or it may do some processing on selected data etc. Game playing is a kind of interactive computer graphics.

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Additional Reading: Introduction