A method for generating a raster image according to a tile drawing command includes acquiring a tile drawing command for repeatedly rasterizing a specified object, determining whether an interval in which the object is repeated in a predetermined direction based on the acquired tile drawing command is an integer pixel width in a coordinate system of the raster image, generating, based on the acquired tile drawing command, another tile drawing command for repeatedly rasterizing the object in the predetermined direction in an interval of an integer pixel width in the coordinate system, wherein the generated another tile drawing command includes a plurality of pieces of information corresponding to a plurality of scaling factors, scaling, based on the another tile drawing command, the object to repeatedly rasterize the object in the predetermined direction.