This invention switches the number of bits per pixel between object types when converting code information into image data, thereby rendering one entire page at high speed while minimizing the influence on print quality. For this purpose, an apparatus analyzes received PDL data, and generates a DL (Display List) serving as a rendering unit. The apparatus determines whether the DL is a character/line image or a halftone image including a photograph image. When determining that the DL is a character/line image, the apparatus resizes the DL in accordance with the resolution of a printer engine, and renders each color component at an 8-bit precision (integer). When determining that the DL is a halftone image including a photograph image, the apparatus resizes the DL in accordance with the resolution of the printer engine, and renders each color component at a 10-bit precision (8-bit integral part+2-bit decimal part).