Visualization Interview Question:

What is Bresenhams line drawing algorithm in Visualization?

Submitted by: Muhammad

In Bresenham's approach the pixel position along a line path are
determined by sampling unit X intervals. Starting from the left end point(X0, Y0)of a
given line we step to each successive columns and plot the pixel whose scan line Y-value
is closest to the line path.Assuming the Kth step in process, determined that the pixel at
(Xk, Yk)decide which pixel to plot in column Xk+1.The choices are (Xk+1, Yk) and (Xk+1,
Yk+1)
Algorithm
Step 1: Input the line endpoints and store the left endpoint in (X0, Y0)
Step 2: Load (X0, Y0) in to the frame buffer
Step 3: Calculate constants
x,
y, 2
y, -2
x, and obtain the decision parameters as
P0 = 2
y -
x
Step 4 : At each Xk along the line, starting at k = 0, perform the following test
If Pk < 0, the next point to plot is (Xk+1, Yk) and
Pk+1 = Pk+2
y
Otherwise, the next point to plot is (Xk+1, Yk+1) and
Pk+1 = Pk+2
y - 2
x
Step 5: Repeat step 4
x times
Submitted by: Muhammad