1. Apparatus comprising a storage medium storing a rendering program having instructions which when executed by a processor will cause the processor to selectively render canvas objects, the instructions of the rendering program for: generating a transparency indicator for each of a plurality of canvas objects included in an electronic document dependent upon whether the respective canvas object includes or does not include transparency characteristics; generating a first pixel map corresponding to only the color data of each of the plurality of canvas objects and a second pixel map corresponding to opacity data of each of the plurality of canvas objects; selectively rendering each of the plurality of canvas objects using either transparency rendering functions or general rendering functions dependent upon the presence or non-presence of the transparency indicator corresponding to each of the plurality of canvas objects; receiving data representative of available memory associated with the rendering operation; and selectively re-rendering objects without reference to the second pixel map dependent upon available memory.