ACCELERATED COMPOSITING OF FIXED POSITION ELEMENTS ON AN ELECTRONIC DEVICE

摘要

A device, system and method are provided for processing structured documents for display. Content of a first viewable portion of the structured document having a fixed position in relation to a viewport is rendered as first rendered image data. Content of a second viewable portion that does not have a fixed position is rendered as second rendered image data. The first and second rendered image data are composited, and a resultant composited image is output for display. In response to a scroll or zoom command applied to the document, and in particular to the second viewable portion, the second rendered image data is updated and composited with the first rendered image data. Compositing can be carried out by a graphics processor separate from a main processor in the electronic device. When no fixed position elements are present in the structured document, the main processor may render the entire content without compositing.