1. A computer program product, stored in a non-transitory computer readable medium, capable of enabling a computer to perform a digital image analysis operation, the digital image analysis operation comprising: receiving settings of a plurality of lines corresponding to one or more image edges of a digital image; identifying a plurality of intersections of the plurality of lines and the one or more image edges of the digital image; and calculating an interval between the plurality of intersections or a path length of the plurality of intersections according to a zooming scale of the digital image.