An image forming apparatus draws line by line an object included in a page. The image forming apparatus includes a sorting unit configured to sort edges of the object included on process target lines in ascending order of coordinates by comparing the coordinates of edges and a drawing unit configured to perform drawing between the edges based on the edges arranged by the sorting unit. The sorting unit compares coordinates to sort other edges on the process target lines with respect to the plurality of edges on the process target lines, which are already sorted, starting with a comparison with the coordinate of one of the plurality of edges specified based on the coordinates of the other edges.