This document provides an introduction to computer graphics, including key concepts such as color models, graphics hardware, and software packages. It outlines the main components of graphics including theory, algorithms, and implementation. Popular graphics applications are discussed such as art/entertainment, image processing, simulation, scientific visualization, and CAD/CAM. Color models like RGB, CMY, HSV are explained. Graphics hardware including line drawing devices, raster devices, and frame buffers are covered at a high level.

1. 1
Computer Graphics
chapter 1
Dr. Jehad Q. O. Alnihoud
Email: jehad@aabu.edu.jo
Phone: 3354

2. RM [1]-2
Books
•F.S. Hill, Computer Graphics Using
OpenGL, Prentice-Hall (2001).
•Mason Woo, OpenGL Programming
Guide, Addison Wesley (2000).
•Hearn and Baker, Computer Graphics,
Prentice-Hall (1997).

3. RM [1]-3
Books (Supplementary reference)
 Foley, V. Dam, Feiner, Hughes, Computer
Graphics Principles and Practice, 2/e,
Addison Wesley, 1997.
 Edward Angel, Interactive Computer
Graphics, Addison Wesley, 1997.
 Zhigang Xiang, Schaum’s Outlines:
Computer Graphics, McGrawHill, 2001.
 Shreiner D, OpenGL Reference Manual,
Addison-Wesley, 2000.

4. RM [1]-4
Course Assessment
 Coursework 50%
First Exam 15%
 Second Exam 15%
Group Project 10%
Lab 10%
 Final Exam 50%
Attendance in both lecture and lab sessions is
compulsory.

5. RM [1]-5
Graphics Applications
 Art and Entertainment
Animations
Movies
Commercials
Special Effects

6. RM [1]-6
Graphics Applications
 Image Processing
Analysis, Reconstruction
Medical Imaging
Movies

7. RM [1]-7
Graphics Applications
 Simulation
Modeling and Analysis
Virtual Environments

8. RM [1]-8
Graphics Applications
 Scientific Visualization
Data Representation and Plotting
3D Views

9. RM [1]-9
Graphics Applications
 CAD/CAM
Industrial Design
Structural Design
Surface Modeling

10. RM [1]-10
Graphics Software Packages
 Early graphics libraries:
GKS (Graphical Kernel System)
 PHIGS
 OpenGL (Silicon Graphics)
 Java2D (Sun Microsystems)
 Java3D (Sun Microsystems)
 VRML (Silicon Graphics)

11. RM [1]-11
Graphics: Main Components
 Theory
Analytical Geometry
Vectors and Matrices
 Algorithms
Eg: Line drawing, Filling etc.
 Implementation
Programming (OpenGL)

12. RM [1]-12
Graphics Hardware
 Line Drawing Devices:
Eg. Pen Plotters
Advantages: Perfect lines, Sharp Diagrams
Disadvantages: Not suitable for filled regions.

13. RM [1]-13
Graphics Hardware
 Raster Devices: Create pictures by displaying
dots
 Eg: Video monitor, dot-matrix printer, laser
printer, ink-jet printer, film recorder
 Advantages: Filled, shaded regions are easily
displayed
 Disadvantages: Jaggies
Pixel

14. RM [1]-14
Pixel Depth
 Pixel depth refers to the number of bits used
to represent a pixel value.
1 bit/pixel: 0
1
2 Levels
(Bi-level image)
2 bits/pixel: 0
0
4 Levels
0
1
1 0
1 1

15. RM [1]-15
Pixel Depth
1 bit per pixel produce 2 levels (bi-
level image).
2 bits per pixel produce 4 levels.
8 bits per pixel produce 256 levels.
In general, if the pixel depth is n, then
it is possible to have 2n levels.

16. RM [1]-16
Raster Display
 Most display used for computer graphics nowadays
are raster displays.
 Image presented in display surface that contains
certain number of pixels. Eg. 480 x 640 (r x c).
 Frame buffer is a region of memory sufficiently large to
hold all the pixel values for display.

17. RM [1]-17
Frame Buffer
 System with 64 color (3 DACs):
Each DAC uses 2 bits/pixel.
Total color: 4 x 4 x 4 = 64
If the display surface is 1024 x 1280, then the
memory required for frame buffer is 0.9375 MB
 Monochrome Video display:
Only one DAC required. 6 planes of memory in frame
buffer gives 26 = 64 level of gray.

18. RM [1]-18
Frame Buffer
 System with 24 bit color (3 DACs):
Each DAC uses 8 bits/pixel. (Total 24 bits/pixel)
Total color: 28 x 28 x 28 = 224
If the display surface is 1024 x 1280, then the memory
required for frame buffer is 3.75MB

19. RM
Basis colors: R, G, B
R: Red=[1, 0, 0]
G: Green=[0, 1, 0]
B: Blue=[0, 0, 1]
C: Cyan=[0, 1, 1]
M: Magenta=[1, 0, 1]
Y:Yellow=[1, 1, 0]
W:White=[1,1,1]
K: Black=[0,0,0]
Color Models: RGB Diagram
• RGB Model is used for colored light sources
• RGB Model is additive

20. RM [1]-20
Complementary Colors: Two colors that combine to form
White. Eg. Red, Cyan.
Gray Values: Every point on the primary diagonal has equal
values for all the components.
Color Models: RGB Cube

21. RM [1]-21
Basis colors: C, M, Y
C: Cyan=[1, 0, 0]
M: Magenta=[0, 1, 0]
Y: Yellow=[0, 0, 1]
R: Red=[0, 1, 1]
G: Green=[1, 0, 1]
B: Blue=[1, 1, 0]
W:White=[0,0,0]
K: Black=[1,1,1]
Color Models: CMY Diagram
• CMY Model is used for colored pigments
• CMY Model is subtractive

22. RM [1]-22
Color Models: RGB <-> CMY
(r, g, b)RGB = (1,1,1)  (c, m, y)CMY
Light
A red colored surface
absorbs cyan from a
white light

23. RM [1]-23
Color Models: HSV HexCone

24. RM [1]-24
H (Hue): 0 to 360 degrees 0: Red, 60: Yellow ….
S (Saturation): 0 to 1 0: Axis, 1: Boundary
V (Value): 0 to 1 0: Vertex, 1: Base
Examples:
Eg. Yellow: [60, 1.0, 1.0]
Black: [ -, -, 0.0]
White: [-, 0.0, 1.0]
Color Models: HSV

25. RM [1]-25
RGB Color Definition (OpenGL)
Set a particular color: glColor3f(r,g,b);
Set a background color: glClearColor(r,g,b,1);
Clear the window to background color:
glClear(GL_COLOR_BUFFER_BIT);