An image processing apparatus includes a first generating unit configured to generate first attribute information of an image and pixels of the image based on rendering commands, a second generating unit configured to perform image area separation processing on an image generated by the first generating unit and to generate second attribute information of the pixels of the image, and an attribute information generating unit configured to generate third attribute information of the pixels of the image based on the generated first attribute information and the second attribute information. In this image processing apparatus, the attribute information generating unit is configured to generate the third attribute information of pixels contained in an object of the image represented by the first attribute information which is identical for each pixel in the object based on a combination of the first attribute information and the second attribute information.