1. An image processing apparatus for receiving image data having a plurality of drawing objects, and performing processing for the image data, comprising: first rasterization means for rasterizing a drawing object at a first resolution; second rasterization means for rasterizing a drawing object at a second resolution lower than the first resolution; and selection means for, when the input image data includes drawing objects which overlap each other, selecting the rasterization means for the overlapping drawing objects on the basis of attributes of the overlapping objects.