Patent ID: 8619333

Claim:
An image forming apparatus comprising: a reception unit configured to receive an electronic document; a generation unit configured to generate a display list containing edge information indicating an outline of an object contained in the electronic document received by said reception unit, fill information for determining a color to fill in an inside of the outline of the object, and control information for controlling image formation of each page that forms the electronic document; and an intersection extraction unit configured to, in a case where a scan line rendering processing for an object in a page of the electronic document is performed for each scan line, extract intersections of the object and the scan line based on the edge information, as edges of the object on the scan line, wherein in a case where a number of intersections of the object and the scan line extracted by said intersection extraction unit becomes not smaller than a threshold, said intersection extraction unit sets a rectangular region which surrounds the object, and extracts, as edges of the object on the scan line, intersections of the rectangular region and the scan line.