DDA Line Drawing Algorithm

Learn and visualize the DDA Line Drawing Algorithm with our interactive tool. Perfect for students and developers exploring computer graphics and algorithm implementation

X1
Y1
X2
Y2

Step-by-Step Calculation of DDA

Starting Points (X1, Y1) = (1, 1)

Ending Points (X2, Y2) = (5, 5).

Step 1: Calculate Dx, Dy, and Slope(m)

Dx = abs(X2−X1) = |5 - 1| = 4

Dy = abs(Y2−Y1) = |5 - 1| = 4

Slope(m) = Dx/Dy = 4 / 4 = 1​

Step 2: Calculating the Number of Steps

Dx = 4 and Dy = 4

Then, the number of steps = 4

Step 3: We get m = 1, Third case is Satisfied

Then X and Y coordinate tend to the Unit interval.

X = X + 1
Y = Y + 1

Initial values: X = 1, Y = 1

Iteration: 1

X = 1 + 1 = 1 and Y = 1 + 1 = 1

Iteration: 2

X = 2 + 1 = 2 and Y = 2 + 1 = 2

Iteration: 3

X = 3 + 1 = 3 and Y = 3 + 1 = 3

Iteration: 4

X = 4 + 1 = 4 and Y = 4 + 1 = 4

DDA Algorithm Case

Case 1: If m < 1

Then x coordinate tends to the Unit interval.

  • xk+1 = xk + 1
  • yk+1 = yk + m

Case 2: If m> 1

Then y coordinate tends to the Unit interval.

  • yk+1 = yk + 1
  • xk+1 = xk + 1/m

Case 3: If m = 1

Then x and y coordinate tend to the Unit interval.

  • xk+1 = xk + 1
  • yk+1 = yk + 1

Table View

Step X Value Y Value Dx Dy X Increment Y Increment Calculation
0 1 1 4 4 1 1 Initial values: X = 1, Y = 1
1 1 1 4 4 1 1 X = 1 + 1 = 1 and Y = 1 + 1 = 1
2 2 2 4 4 1 1 X = 2 + 1 = 2 and Y = 2 + 1 = 2
3 3 3 4 4 1 1 X = 3 + 1 = 3 and Y = 3 + 1 = 3
4 4 4 4 4 1 1 X = 4 + 1 = 4 and Y = 4 + 1 = 4