Image data output apparatus with display range designation means

Claim 1

An image data output apparatus, comprising: image data storage means for storing image data representing a large image of a certain area; image data storage controller means coupled to said image data storage means, for dividing the image data of the large image of said certain area into a given number of sets of partial image data, each of which sets corresponds to a different partial image area of predetermined size smaller than said large image of said certain area, and including means for storing the image data in units of the number of sets of partial image data at determined locations in said image data storage means; page link memory means for storing connecting data representing image connecting relationships among each of said sets of partial image data for enabling the image data of said large image to be reproduced from connected ones of said sets of partial image data by an output device; frame memory means for storing image data corresponding to a plurality of sets of partial image data stored in said image data storage means, said plurality of sets together representing adjacent partial image areas of said large image wherein the image areas when connected have end boundaries; output range designation means for arbitrarily designating a window area range of image data to be reproduced by the output device from the image data corresponding to the plurality of sets of partial image data stored in said frame memory means; and control means coupled to said image data storage controller means, said page link memory means, said frame memory means and said output range designation means, including means for reading out end boundary adjacent image data representing a correct connecting relationship among the sets of partial image data from said image data storage means in accordance with the connecting data in said page link memory means when a designated window area range reaches an end boundary among the sets of partial image data in said frame memory means, and reallocation means for storing the readout end boundary adjacent image data in said frame memory means in place of part of current image data stored in said frame memory means; wherein only those sets of partial image data stored in said image data storage means which are necessary for reproduction in the designated window area range of the large image, are allocated in said frame memory means.