Sketch Line Segment That Joining By Using Bresenham Line Algorithm
Example: Sketch line segment that joining (20, 10) and (25, 14) by using Bresenham line generation algorithm.
Solution: (x_{0}, y_{0}) → (20, 10) ; (x_{1}, y_{1}) → (25, 14)
m = (y_{1}- y_{0})/(x_{1} - x_{0})
= (14- 10)/(25 - 20)
= 4/5 < 1
Like, m = (Δy)/ (Δx)
= 4/5 =› Δy = 4
→ plot point (20, 10)
p_{i} = 2Δy - Δx
i = 1: p_{i} = 2 * 4 - 5 = 3
Here p_{1} > 0 consequently x_{0} ← 21; y_{0} ← 11 now plot (21, 11)
i = 2 as p_{1} > 0
∴p_{2} = p_{1} + 2(Δy - Δx)
= 3 + 2 (4 - 5) = 3 - 2 = 1
p_{2} > 0; hence x_{0} ← 22; y_{0} ← 12 plot (22,12)
i = 3 as p_{2} > 0
∴p_{3} = p_{2} + 2 (Δy - Δx) = 1 + 2 (4 - 5) = - 1
p_{3} < 0 ∴x_{0} ← 23
y_{0} ← 12
plot (23, 12)
i = 4 as p_{3} < 0
∴p_{4} = p_{3} + 2Δy
= -1 + 2 * 4 = 7
∴ x_{0} ← 24; y_{0} ← 13
plot (24, 13)
i = 5 as p_{4} > 0
∴p_{5} = p_{4} + 2 (Δy - Δx)
= 7 + 2 (4 - 5) = 5
x_{0} ← 25; y_{0} ← 14
Plot (25, 14)
{for i = 6, x0 will be > x_{i} so algorithm terminates