Bresenham lines w/o diagonal movement

Question

Is there a modified Bresenham algorithm, where the step from one pixel to the next one isn\'t allowed to be diagonally, just horizontally or vertically? Or any other algorit

Answer 1

Should be a trivial modification - let's say you're in the quadrant I - i.e. going up and to the right. Instead of doing a diagonal, do an up... and then a right.

Instead of:

  for x from x0 to x1
             plot(x,y)
             error := error + deltaerr
             if error ≥ 0.5 then
                 y := y + 1
                 error := error - 1.0

Something like this:

for x from x0 to x1
         plot(x,y)
         error := error + deltaerr
         if error ≥ 0.5 then
             y := y + 1
             plot(x,y)
             error := error - 1.0