Chapter 3
Scan Converting Lines
Given: p1 = (x1,y1) and p2 = (x2,y2)
Objective: Find pixels which approximate the line segment (p1,p2)
Basic Algorithm
slop := (y2 - y1) / (x2 -x1)
y := y1
FOR x := x1 TO x2 DO
PaintPixel(x,round(y))
y := y + slop
END
DRAWBACKS
- Gaps occur for slop > 1
- Division ‘/’ in floating arithmetics is slow
- Rounding is slow
The last 2 problems are aggrevated because they are within a loop
Called also Digital Differential Analazer (DDA) algorithm