Page 22 - DCAP313_LAB_ON_COMPUTER_GRAPHICS

Lab on Computer Graphics

Notes generated imagery can be categorized into several different types: 2D, 3D, and animated
graphics. As technology has improved, 3D computer graphics have become more common, but
2D computer graphics are still broadly used. Computer graphics has emerged as a sub-field of
computer science which studies methods for digitally synthesizing and manipulating optical
content. Specialized fields have been developed like information visualization, and scientific
visualization more concerned with “the visualization of three dimensional phenomena where
the emphasis is on realistic renderings of volumes and surfaces”.

A picture may take the form of a static image or that of an animated form. Whatever the outcome,
a system will need to incorporate mechanisms to promote interaction; between the user and the
system itself. For interaction to take place, the system needs to employ tools to facilitate input
variation and output devices which work on a transitory basis. Computer graphics involves
display, manipulation and storage of pictures and experimental data for suitable visualization
using a computer. Typical graphics system comprises of a host computer with support of fast
processor, large memory, frame buffer.
• Display devices (colour monitors),

• Input devices (mouse, keyboard, joystick, touch screen, trackball)
• Output devices (LCD panels, laser printers, colour printers. Plotters etc.)
• Interfacing devices such as, video I/O, TV interfaces etc.

Figure 2.1: Process of Graphics System

Computer Graphics systems could be active or passive. In both cases, the input to the system
is the scene description and output is a static or animated scene to be displayed. In case of
active systems, the user controls the display with the help of a GUI, using an input device.
Computer Graphics is at the present time, a significant Computer of approximately all systems
and applications of computers in every field of life. Various fundamental concepts and principles
in Computer Graphics are:
Display Systems: Storage displays, Random scan, Raster refresh displays, CRT basics, video
basics, Flat panel displays.
Transformations: Affine (2D and 3D): Rotation, Translation, Scale, Reflection and Shear. Viewing:
The Camera Transformations -perspective, orthographic, isometric and stereographic views,
Quaternion.
Scan Conversion and Clipping: Drawing of Points, Lines, Markers, Curves, Circles, Ellipse,
Plotline, and Polygon. Area filling, fill-style, fill pattern, clipping algorithms, anti-aliasing etc.
Hidden Surface Removal: Back face culling, Painter’s algorithm, scan-line algorithm, BSP-trees,
Z-buffer/sorting, Ray tracing etc.

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