Data display

Abstract

A technique for achieving read-time animation in bit-map data displays in apparatus having a display memory in which digital codes are stored to give the color and/or luminance of each pixel of the display and the display memory is accessed repeatedly in a recurrent display scan cycle to read-out the digital codes to produce the display. The time available for modifying the contents of the display memory to achieve animation of an object against a fixed background is very small and access to the display memory for the display scan and for writing-in new digital codes must not be in conflict. The present invention proposes a method of continually modifying the display memory content, to achieve object animation, in which the shape of an object is coded into a machine code program (e.g. by a compiler) before the display is run and then the machine code program is used as a sub-routine as the display is run to move the data for the object shape (with or without modification) to different memory locations of the display memory, with the data for the background areas involved being saved and re-written as the animation progresses and the object shape moves over the background. FIG. 1 shows a block diagram of data display apparatus in which the invention can be embodied.