Page 49 - DCAP504_Computer Graphics

Computer Graphics

The following figure 4.2 depicts scan converting a line.

Figure 4.2: Scan Converting a Line

In figure 4.2, the coordinates of the last chosen pixel are (x i , y i ). Choose the next pixel between the
bottom pixel S and the top pixel T.
If S is chosen,
x i+1 =x i +1

y i+1 =y i
If T is chosen,

x i+1 =x i +1
y i+1 =y i +1
The actual y coordinate of the line at x=x i+1 is:

y=mx i+1 +b
i.e., y=m(x i +1)+b

The distance from S to the actual line in the y direction is:
s=y-y i
The distance from T to the actual line in the y direction is:

t=(y i +1)-y

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