System and method for producing an animated image of a moving object on a video display screen wherein digital data for a plurality of progressively different images of the object is stored in a memory and read out during successive frames of the picture. The data from the memory is combined with data corresponding to the position at which the image of each frame is to be displayed on the screen, and the images are displayed in accordance with the combined image and location data. Background of the Invention

In the field of raster scan computer graphics display equipment, an apparatus for the transformation of picture information specified as line segments defined in terms of a two dimensional planar coordinate system describing the display raster into a form convenient for display on said raster, wherein for each scan line to be displayed the appearance thereof being determined by passing pieces of information describing line segments together composing the picture from a display file memory, sending them through a display processor to calculate the positions at which they cross the scan line, and placing the resulting pieces of information in a scan line buffer memory ordered by their precedence in the display of the scan line, during the display of a previously calculated scan line.

Information is displayed in alphanumeric form on a screen of a gas discharge tube having row and column electrodes with intersections. Gas in the tube is ionized in response to a predetermined ionizing voltage existing between the rows and columns at selected intersections to cause a visible signal to be derived at the intersections. Logic means applies ionizing voltages to column electrodes of the screen in a sequential scan. A video scan controller has one input responsive to signals representing coded characters to be displayed column by successive column. A character generator responsive to signals derived from the scan controller activates a controlled logic circuit so ionizing voltages are applied to predetermined row electrodes in the screen to activate the selected intersections to display the coded characters.

A raster type display apparatus includes interlaced even-and-odd frames. A digital memory of a computer stores line segment data in locations which are sequentially read out to form a line segment display with overlapping line segments. An off-scale detector prevents a line segment directly between the data points and creates a pair of line segments at the top and bottom of the display screen. An extended line from a break point in a curve to screen bottom is also prevented. Resettable registers monitor the carrier bits of digital multiplier and adder and are connected by an even-odd detector to actuate an exclusive "OR" gate to complement the output and generate the appropriate split display.

A system for writing cursors on a raster scanned television screen that uses the microprocessor in a display controller to produce blocks of data defining the parameters of vectors that compose the cursor. The blocks are put in a first-in first-out memory during a vertical blanking inerval or during active picture time. Each block specifies where writing of a cursor segment is to start and stop on a horizontal scan line and it also specifies a repeat count that indicates the number of lines on which the segment is to be written. Each block contains a delta value to indicate how much, if any each segment is to be displaced left or right from line to line so vertical and angulated vertical vectors can be produced. The blocks are read out of the memory consecutively by a circuit that converts the segment start and stop data to pixel counts. Pixel counters determine the writing start and stop points. When the number of horizontal lines on which segments are written equals the repeat count, the next block is processed.