Consider a line AB with A = (0, 0) and B = (8, 4). Apply a simple DDA…
2017
Consider a line AB with A = (0, 0) and B = (8, 4). Apply a simple DDA algorithm and compute the first four plots on this line.
- A.
[(0, 0), (1, 1), (2, 1), (3, 2)]
- B.
[(0, 0), (1, 1.5), (2, 2), (3, 3)]
- C.
[(0, 0), (1, 1), (2, 2.5), (3, 3)]
- D.
[(0, 0), (1, 2), (2, 2), (3, 2)]
Attempted by 141 students.
Show answer & explanation
Correct answer: A
Key data: A = (0, 0), B = (8, 4)
Compute differences and steps:
dx = 8 - 0 = 8
dy = 4 - 0 = 4
steps = max(|dx|, |dy|) = 8
Increments per step:
x increment = dx / steps = 8 / 8 = 1.0
y increment = dy / steps = 4 / 8 = 0.5
Generate points starting from (x,y) = (0,0). After each step compute new x and y and round to nearest integer for the pixel plot.
Step 0: x = 0.0, y = 0.0 → plotted pixel (0, 0)
Step 1: x = 1.0, y = 0.5 → round y to 1 → plotted pixel (1, 1)
Step 2: x = 2.0, y = 1.0 → plotted pixel (2, 1)
Step 3: x = 3.0, y = 1.5 → round y to 2 → plotted pixel (3, 2)
Therefore the first four plots are: (0, 0), (1, 1), (2, 1), (3, 2).