System for text display with plural page memory and flag memory

Claim 1

An image display apparatus comprising image memory means having plural display areas corresponding to areas of a visual display and for storing image signals of plural pages, each page being formed of a plurality of packets of data, and read out means for reading out said image signal in said image memory means and supplying it to an image display means for visual display, in which said image memory means includes a pattern memory for storing plural line data of the image to be displayed, and said image display apparatus further comprises flag memory means having plural flag areas corresponding to respective ones of said plural display areas of said image memory means and in which said plural flag areas include plural line flag areas corresponding to each line of said image to be displayed, flag control means for setting a flag of a corresponding display area to a first value when an erase code contained in one of said plurality of packets is received and setting said flag to a second value when an image signal contained in said plurality of packets is received, and read out control means for controlling said read out means so as to supply a blank signal instead of the image signal of said corresponding display area to said image display means when said corresponding flag is set to said first value, and to supply the image signal in said corresponding display area to said image display means when said corresponding flag is set to said second value.