Patent ID: 7646927

Claim:
An image processing apparatus comprising: a block decompression unit to decompress, block by block, a compressed code having a plurality of blocks into which data of an image is divided, the compressed code being encoded block by block; a rendering control unit to cause one or more of the blocks corresponding to an area to be rendered of the image corresponding to a rendering region of a display unit to be extracted based on a signal indicating the rendering region of the display unit, and to cause a part of the compressed code corresponding to the extracted one or more of the blocks to be decompressed by the block decompression unit and rendered on the display unit before causing a remaining part of the compressed code to be compressed; a rendered image change instruction unit to give an instruction to change the area to be rendered of the image from a first area to a second area of the image; a changed image rendering unit to, when the instruction is given by the rendered image change instruction unit, decompress part of the compressed code that corresponds to one or more of the blocks of the data of the image that correspond to the second area of the image, and render the second area of the image in the rendering region of the display unit; a predicted block decompression unit to predict an area of the image to which the area to be rendered is changed from the first area based on the instruction given by the rendered image change instruction unit, and decompress, in advance, part of the compressed code that corresponds to a block of the data of the image that corresponds to the predicted area, wherein the changed image rendering unit renders the predicted area of the image in the rendering region when the block corresponding to the predicted area is identical to the block corresponding to the second area; and a rendering position change unit to change the area to be rendered, wherein the predicted block decompression unit predicts the area of the image to which the area to be rendered is changed from the first area based on a characteristic of the rendering position change unit when the rendered image change instruction unit is based on the rendering position change unit, wherein when the rendering position change unit performs pixel-by-pixel scrolling using a scroll bar, the predicted block decompression unit predicts that a block existing in a first direction from the first area is a next block to be rendered, the first direction being perpendicular to a second direction in which the scrolling has been performed to the first area.