It is a power point presentation on Computer Graphics...

1. Shri Vaishnav Institute
Of Management
Presentation On Computer
Graphics

2. Applications
Of Computer
Graphics
Frame
Buffer
Line
Algorithm

4. Computer Aided Design
Computer Aided Design(CAD) is the Use of Computer
System to Assist in the Creation , Modification , Analysis or
Optimization of Design.

5. Visualization
Visualization is any Technique For Creating Images , Diagrams
or Animations
To Communicate A Message.

6. Animation
Animation is the Process Of Creating a Continuous Motion
& Shape Change illusion by means of rapid display of a
Sequence of static Images that Minimally differ from each
other.

7. Computer Games
Computer Games are Video Games played on a
General Purpose Personal Computer

8. Frame Buffer
A Frame Buffer is a Large , Contiguous Piece of Computer
Memory(RAM) that stores Picture Definition. This Memory Area Holds
the Set of intensity values for all the Screen points and then retrieved
from the frame buffer and painted on the Screen One Row(Scan Line)
at a time. Each screen point is referred to as a Pixel or pel or Picture
Element.

9. LINE DRAWING ALGORITHM

10. Line Drawing Algorithm
There are two basic line drawing algorithm…..
DDA Line Drawing Algorithm
Bresenham’s Line Drawing Algorithm

11. DDA Line Drawing Algorithm
Programmer Specifies
(x,y) values of end pixels
Need Algorithm to find
out which intermediate
pixels are on line path
Pixel (x,y) constrained to
integer values
Actual Computed
intermediate line values
may be floats
Rounding May
Be Required

12. 0 1 2 3 4 5 6 7 8 9 10 11 12
8
7
6
5
4
3
2
1
(3,2)
(9,6)
DDA Line Drawing Algorithm

13. DDA Line Drawing Algorithm
DDA stands for “Digital-Differential Analyzer”.
It’s a “Scan-Conversion” line drawing algorithm.
It’s mainly based on calculating either Δx (dx)
or Δy (dy)…

14. DDA Line Drawing Algorithm
Slope – Intercept Line Equation
y = m . x + b
Given Two End Points (x0,y0) and (x1,y1).
How To Compute m and b ?
(x0,y0)
(x1,y1)
dx
dy
m = dy / dx = (y1 – y0) / (x1 – x0)
b = y0 – m * x0
Δy = m * Δx
Δx = Δy/m

15. DDA Line Drawing Algorithm
If a line with positive slope (+m) or it’s less than and
equal to 1(m<=1), then we set ‘x’ at unit interval(Δx=1)
And compute each successive ‘y’ value by using following
Formula:-
yk+1 = yk + m
Where subscript ‘k’ takes integer values starting from 1,
For the first point, and increases by 1 until the final end
point is reached..
Left to right

16. DDA Line Drawing Algorithm
If a line with positive slope (+m) or it’s greater than
1(m>1), then we reverse the rule of ‘x’ and ‘y’, that is set ‘y’
at unit interval(Δy=1) and compute each successive ‘x’ value
by using following Formula:-
xk+1 = xk + 1/m
Where subscript ‘k’ takes integer values starting from 1,
For the first point, and increases by 1 until the final end
point is reached..
Left to right

17. REFRANCE
 BOOK REFRANCE
 “Computer Graphics C Version” by “Donald Hearn And M. Pauline
Baker”.

18. Presentation Powered By :
Ashish Sharma
Lokendra Prajapati