When processing and printing a vector image, curves present in the image are converted
to a series of short straight line segments. The length of these lines are very short
and your eye can only see a curve. The setting that determines the length of these
straight line segments is called "flatness".
Flatness settings can be set in Adobe
Photoshop, Adobe Illustrator, or other illustration programs are generally applied
to clipping paths in images and on vector objects.