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