A method for generating a presentation of a region-of-interest in an original image for display on a display screen, comprising: establishing a lens for the region-of-interest, the lens having a magnified focal region for the region-of-interest at least partially surrounded by a shoulder region having diminishing magnification, the focal region having a perimeter defined by a radius r from a line segment; receiving one or more signals to adjust at least one of the radius r and a length len of the line segment to thereby adjust the perimeter; and, applying the lens to the original image to produce the presentation.