Abstract: A graphic display device of the type which receives data and instructions from an external computer and displays graphic patterns such as alphanumeric characters, symbols, etc., upon a cathode ray tube in accordance therewith. The graphic display device has a pattern generator for storing luminance data controlling the formation on the cathode ray tube of predetermined patterns, and a refresh memory for receiving and storing data designating the particular arrangement of patterns to be displayed, and is characterized by an arrangement reducing the required capacity of the pattern generator memory.

Abstract: A graphic display device of the type which receives instructions from an external computer and, by successively scanning the rasters of a display matrix, displays patterns such as alphanumeric characters, symbols, etc. upon a cathode ray tube. The graphic display device has a pattern generator which stores patterns in raster form and generates signals for forming such patterns upon receipt of a pattern address signal designating the particular pattern to be formed, and a repeating raster designation signal designating the particular raster of stored pattern information to be accessed for each scan of the display matrix. Pursuant to the invention, the graphic display device comprises pattern shifting means for shifting, on demand and in an amount selected by the external computer, the display of a pattern in a direction transverse to the direction of raster scanning.