1. An image forming apparatus comprising: a unit configured to generate a normalized tile image, which is a unit image of repetition in a tile image; a unit configured to calculate the number of the normalized tile images that can be arranged in a drawing region after variable magnification of the tile image with a predetermined variable magnification rate; and a unit configured to generate a tile image in which the calculated number of the normalized tile images are arranged in the drawing region after the variable magnification, as the tile image after the variable magnification, if the calculated number is a first threshold value or more.