Patent ID: 7633508
Filing Date: 2009-12-15
Classification: G09G

Abstract:
1. A data transfer apparatus comprising: a reference-data storing unit that stores reference data for determining, when an instruction to display image data stored in a predetermined address space on a same display position as a display position of other display data is received, whether to display the image data by overwriting the display data; a data converting unit that converts the image data into color converted display image data in a format for display; a transparency determining unit that determines whether a first pixel value of the color converted 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 the transparency determining unit determines that the first pixel value coincides with the second pixel value, the display image data to the display address space; a read-transfer-width register that stores an image width to be sent to the data converting unit from among the image data; a transfer-source image-folding-width register that stores an image width of the image data; a read-processing-address register that stores a read-processing address that is an address of image data being converted by the data converting unit, the read-processing-address register taking the read-start address as a reference and shifting to a next address one by one with each step of a transfer process; a number-of-read-lines register that stores number of lines of the image data already converted; a read-address calculating unit that calculates the read-processing address by adding one to the number-of-read-lines register upon reaching an address set at the read-transfer-width register with a shift of the read-processing address one by one in units of transfer, and adding a value obtained by multiplying the number of read lines by an address width set in the transfer-source image-folding-width register to the read-start address; and a data reading unit that reads the image data corresponding to the read-processing address calculated by the read-address calculating unit in the predetermined address space, wherein the data converting unit converts the image data read by the data reading unit into the display image data.