An object of the present invention is to provide an image forming apparatus and an image forming method by which image data are prepared for performing image processing at high speed and while saving memory. Vector data are generated from data scanned by a scanning unit. In this process, a printing direction is determined from a content input from an operating unit or information on an outputting device. If the printing direction and the scanning direction differ, control of an order of the data is performed to prepare a document after rotation.