Method, apparatus and system for rendering regions of an image

A method of rendering an image is disclosed. A plurality of non-overlapping regions of the image is received, each region being associated with a fill compositing stack comprising a plurality of levels to be composited to determine colour data of said region, each level being defined by a compositing operation and a colour operand. Equivalent ones of the compositing stacks are identified, the equivalent compositing stacks being defined by equivalent sets of graphical commands applied to different colour operands. Regions associated with the equivalent compositing stacks are selected. Pixels corresponding to the selected regions are combined into a data structure. The pixels are concurrently rendered using the data structure to render the image.