Method and apparatus for managing graphics layers within a data processing system

A data processing system comprising:

• a graphics display component for creating an image to be displayed, the graphics display component comprising:
• a layer selection module configured to identify a set, M, of active layers for at least one pixel to be displayed;
• a display controller unit, DCU, operably coupled to the layer selection module and comprising a blend manager;
• and
• at least one processor and one or more processing units;
• wherein the data processing system is characterised by the at least one processor configured to determine whether a number, m, of active layers in the set, M, exceeds a blend limit, n, of a maximum number of graphical surfaces that can be blended simultaneously by the DCU and, in response thereto, identify a subset N of up to n layers from the set M of active layers;
• the blend manager configured to bind the subset N of active layers directly to the DCU and output any excess active layers in the set, M, that exceeds the n layers to at least one selected processing unit for blending;
• and
• the DCU configured to generate composite pixel data to be displayed based on separate blends from the DCU and the at least one selected processing unit that blended the excess active layers in the set, M,
• wherein the processor is configured to determine whether the number, m, of active layers in the set, M, exceeds the blend limit, n, by determining for each rectangle set Sx in a first candidate set, CSx and each rectangle set Sy in a second candidate set, CSy, whether an intersect Sx exists with Sy to obtain a candidate solution set, S.