US Patent 7633508 Data transfer apparatus

A reference-data storing unit stores reference data for determining whether to display image data by overwriting display data. A data converting unit converts the image data into display image data. A transparency determining unit determines whether a first pixel value of the display image data obtained through a color conversion by the data converting unit coincides with a second pixel value of the reference data stored in the reference-data storing unit. A data transfer unit that transfers, when it is determined that the first pixel value coincides with the second pixel value, the display image data to a display address space.