Computer Graphics is a sub-field of computer science and is concerned with digitally synthesizing and manipulating visual content. OR Computer Graphics is the study of techniques to improve communication between human and machine. The word computer graphics means picture , graph or sense is dream with the help of computer.

1. Definition of Computer Graphics
Computer Graphics is a sub-fields of computer science and is concerned with
digitally synthesizing and manipulating visual content.
Computer Graphics is the study of techniques to improve communication between human and
machine.
The word computer graphics means picture , graph or sense is dream with the help of computer.
OR

2. Application of Computer Graphics
• Engineering / Scientific Software, Business Software.
• T.V. channels, space simulation training.
• PCB designing, map preparation.
• User Interface, Animation.
• Making Charts, Image Processing.
• Office Automation.
• Desktop Publishing.
• CAD / CAM.
• Art and Commerce.
• Process Controlling.
• 'Visual Effects' in Movies and Computer Games.

3. Pixel and Frame Buffer, Resolution.
The pixel is the smallest addressable screen element. It is the smallest piece
of the display screen which we can contact.
Each pixel has name on address. Computer Graphic images are made by
setting the intensity and color of the pixels which compose the scree.
The intensity value for all pixels are placed into an array in our computer
memory. This array, which contacts an internal representation of the image
is called the frame buffer.
It collects and stores pixel values for use by the display choice.
Resolution useless to the numbers of dots on the screen.
It is expressed as a pain of numbers that give the number of dots on a
horizontal line and the number of such vertical line.
ex. 640 X 480, 800 X 600 etc.

4. Stages for graphics pipeline.
1. Modeling transformation.
2. Per-vertex lighting.
3. Viewing transformation.
4. Primitive generation.
5. Projection transformation.
6. Clipping.
7. Scan conversion or rasterization.
8. Texturing, fragment shading.
9. Display.
10. The graphics pipeline in hardware.

5. Bitmap Graphics VS Vector Graphic (Com)
SR Bitmap Graphics Vector based Graphics
1 Pixels are used to form Bitmap images. Mathematical formulas are used to form
vector based images.
2 Larger in size than vector based. Smaller in size than bitmap based.
3 Bitmap graphics are affected by resolution. Does not affect by resolution.
4 Modification in bitmap graphics is more
difficult.
Modification in vector graphics is easy.
5 Conversion of Bitmap graphics to Vector
graphics is more difficult.
Vector graphics can be converted in to
Bitmap graphics easily.
6 More suitable for complex images. Not appropriate for complex images.
7 e.g. GIF, JPEG, BMP, etc. e.g. Postscripts and True Type fonts.

6. Text Mode & Graphics Mode
Text Mode
80 columns
25rows
Graphics Mode
640
480

7. Graphics Mode functions
1. Initgraph
2. Path ("C:/tc/bgi")
3. Line()
4. Closegraph()
5. Restorcrtmode()

8. Raster Scan display
User program Frame buffer Raster display

9. Random Scan display

10. Random ScanVS Raster Scan (Com)
SR Random Scan Raster Scan
1 Random scan operate by directing the
electron beam to only those parts of the
screen where the picture is to be drawn.
The electron beam starts at top left corner
of the screen and moves horizontally to the
right.
2 Creation of diagram using random scan
becomes easier, so can be used in engineering
and scientific drawings.
Raster graphics can be used in animation.
3 Pen plotters and direct storage view tubes
(DVST) devices are used.
Cathode ray tubes (CRT) are used.
4 The cost of devices used for random scan is
much higher.
The cost of devices used for raster scan is
much cheaper.
5 Requires less memory. Requires more memory.
6 Requires intelligent electron beam. i.e.
processor controlled.
No such requirement.

11. Electron gun of CRT

12. A
B
C
B
A
Fig 1.5.1 Fig 1.5.3Fig 1.5.2
Current
position
X, Y
A
B
C
D E
Current
position
DX
DY
X, Y
Fig 1.5.4
A
B
C
D
A
B
C
D
Fig 1.5.5 Fig 1.5.6
Primitive Operation

13. Latest trends in Computer graphics
A. Virtual reality (VR)
Virtual reality means Computer generated environment to interact with and be
immersed in.
It immerses users in a computer graphical digital environment.
It can also be defined as a creation of simulated environment by using computer
technology.
we can look in every direction as if we are physically at that location.
B. Augmented Reality (AR)
In this technology users interact with the real world while digital controls are
address to it.
is the result of applying technology to superimpose information such as sounds,
images and text are the real world which we see.