**Example 1:** Draw line segment from point (2, 4) to (9, 9) by using Digital Differential Analyzer algorithm.

**Solution:** We know usual equation of line is specified via

y = mx+c; here m =( y_{1} - y_{0}/( x_{1} - x_{0})

Specified (x_{0}, y_{0}) → (2, 4) ; (x_{1}, y_{1}) → (9, 9)

⇒ m = ( y_{1} -y_{0})/( x_{1} - x_{0})

= (9 - 4) /(9 - 2)= 5/7..that is 0< m<1

C = y_{1}- mx_{1} = 9 - ((5/7)* 9) = (63 - 45)/7 = 18/7

Conversely, by Equation of line (y = mx + c) we have

Y = (5/7)x + (18/7)

DDA Algorithm Two case:

Case 1: m < 1 x_{i} + 1 = x_{i} + 1 y_{i} + 1 = y_{i} + m

Case 2: m > 1 x_{i} + 1 = x_{i} + (1/m)

y_{i} + 1 = y_{i} + 1

Since 0 < m < 1 so as per to DDA algorithm case 1

x_{i} + 1 = x_{i} + 1 y_{i} + 1 = y_{i} + m

Specified (x_{0}, y_{0}) = (2, 4)

1) x_{1} = x_{0} + 1 = 3

Y_{1} = y_{0} + m= 4 +5/7= 4 (5/7)

Place pixel (x_{0}, round y, colour)

That is put on (3, 5)

2) x_{2} = x_{1} + 1 = 3 + 1 = 4

y_{2} = y_{1} + m = (33/7) +(5/7)

Place on (4, 5)

Likewise go on till (9, 9) is reached.