Patent ID: 8941675
Filing Date: 2015-01-27
Classification: G06F,G09G

Abstract:
1. A method in an electronic device for processing a structured document including at least a main region and a subregion within the main region, the method comprising: creating a backing store for storing rendered content in memory of the electronic device, the backing store including an available pool of tiles for storing image data; rendering, as main rendered image data, at least a portion of the main region associated with a first viewport; rendering, as second rendered image data, at least a portion of the subregion associated with a second viewport; allocating, from the available pool of tiles, a first subset of tiles for storing the main rendered image data and a second subset of tiles for storing the second rendered image data; storing the main rendered image data in the first subset of tiles; storing the second rendered image data in the second subset of tiles; outputting, to a display interface, viewable portions of selected tiles from the first subset of tiles and the second subset of tiles that are within the first viewport and the second viewport; in response to a change in either the first viewport or the second viewport, when it is determined that rendered image data required for the changed viewport is not stored in the subset of tiles corresponding to the changed viewport and a quantity of unused tiles in the available pool of tiles is insufficient to store the required rendered image data, outputting viewable portions of newly viewable tiles of the subset of tiles corresponding to the changed viewport.