Graphic symbol generator

In a graphic symbol generator for use with a data processing system employing a cathode-ray tube display and using two digitally controlled analog integrators, one for each of two orthogonal X and Y axes of said cathode-ray tube display to generate spaced parallel strokes, where inputs to said integrators are from separate digital-to-analog converters connected to separate registers, an improvement comprising means for programming the rates and polarities of change in the outputs of the integrators in the form of digitally coded numbers loaded into said registers by a stored program in said data processing system to provide programmed X and Y beam deflection rates which cooperate to generate strokes at an angle between 0.degree. and 90.degree. with respect to said axes as required in response to the ratio of one of said numbers to the other.

In a programmed digital data processing system having means for generating spaced graphic symbols on a line across the face of a cathode-ray tube, said means employing X and Y deflection systems for producing spaced parallel strokes of an electron beam, said strokes beginning on a line common to all symbols as a baseline, the first of said strokes starting at a designated point specified on a coordinate system having orthogonal X and Y axes, where said X and Y deflection systems cooperate to place said beam on any point on the face of said cathode-ray tube in response to X.sub.p and Y.sub.p signals, said graphic symbol generating means having means for turning said beam on and off as required by counting units of stroke length from said baseline to determine the on and off points of stroke elements which make up the symbol, the improvement of means for starting each stroke from said baseline at the bottom of each symbol, means for terminating each stroke at the turn-off point of the last of one or more elements, and means for programming an offset of said starting point in a direction normal to said baseline according to the needs of each symbol, thereby accommodating symbols which extend below said line common to all symbols and providing for placement of any symbol above or below said line.

In a programmed digital data processing system having means for generating spaced graphic symbols on a line across the face of a cathode-ray tube, said means employing X and Y deflection systems for producing spaced parallel strokes of an electron beam, said strokes beginning on a line common to all symbols as a baseline, the first of said strokes starting at a designated point specified on a coordinate system having orthogonal X and Y axes, where said X and Y deflection systems cooperate to place said beam on any point on the face of said cathode-ray tube in response to X.sub.p and Y.sub.p signals, said graphic symbol generating means having means for turning said beam on and off as required by counting units of stroke length from said baseline to determine the on and off points of stroke elements which make up the symbol, the improvement of means for starting each stroke from said baseline at the bottom of each symbol, means for terminating each stroke at the turn-off point of the last of one or more elements, means for generating said strokes, means for adding programmed values to at least one of said X and Y coordinates of said starting points at the end of each stroke;

• and means for programming said values to be added to said X and Y coordinates, whereby width of said symbol is controlled.

In apparatus for displaying graphic symbols on an imaginary line using a cathode-ray tube and employing a beam control system, means operative on said beam control system for starting at specified points each of a plurality of parallel strokes required for each symbol on said line, means operative on said starting means for programming an offset of said points below said imaginary line along which spaced symbols are displayed in sequence in order to specify starting points for strokes of symbols which extend below said imaginary line, and means operative on said starting means for programming an offset of said points in a direction parallel to said imaginary line from an offset position otherwise specified for italicized symbols that extend below said line as said line of spaced symbols is displayed.