Patent ID: 8248411

Claim:
An apparatus comprising: a grouping unit configured to Z-axis-sort rendering data, to read the rendering data in the order of data higher in the Z-axis, to group text rendering data that does not overlap other rendering data into a first group, and to group rendering data that overlaps other rendering data and rendering data other than text rendering data into a second group; a first rendering unit configured to render the text rendering data grouped into the first group using a painter's algorithm; a second rendering unit configured to render the rendering data other than text grouped into the second group using a scanline algorithm; and a combining unit configured to combine an image rendered by the first rendering unit and an image rendered by the second rendering unit, wherein the rendering data grouped into the first group is specified by Z-axis-sorting the rendering data, reading the rendering data in the order of data higher in the Z-axis, determining whether the read rendering data is text rendering data, when the read rendering data is determined to be text rendering data, determining based on a circumscribing region table whether the determined text rendering data has a circumscribing region overlapping a circumscribing region of the rendering data that has been already read, when the determined text rendering data does not a circumscribing region overlapping the circumscribing region of the rendering data that has been already read, the determined text rendering data is marked as belonging to the first group, and storing the circumscribing region of the rendering data that has been already read into the circumscribing region table.