Method and apparatus to calculate any porter-duff compositing equation using pre-defined logical operations and pre-computed constants

摘要

A method of performing a blending operation between a first pixel having a first pixel alpha value and a first pixel color data value and a second pixel having a second pixel alpha value and a second pixel color data value using a pre-defined set of logical operations and an associated set of pre-computed constant that includes calculating a first pixel blending factor and a second pixel blending factor based upon a selected Porter-Duff compositing equation, the first pixel alpha value, and the second pixel alpha value, such that there are no decisions to be made in an innermost calculation loop.