Abstract: A memory device having a plurality of addressable memory locations, each of which can be defined uniquely by an address word having an X component and a Y component, which memory locations correspond respectively to grid points in a rectangular array at a pitch dX in the X direction and a pitch dY in the Y direction, is loaded with data values Q. In a first operating cycle, a first address word defining a memory location corresponding to a first grid point is generated. In a second cycle, a first value of Q as a function of X and Y is computed, and concurrently a second address word defining a memory location corresponding to a second grid point is generated. In a third cycle, the first value of Q is compared with a previous value of Q for the first grid point, and concurrently a third address word defining a memory location corresponding to a third grid point is generated and a second value of Q is computed.

Abstract: A memory device having a plurality of addressable memory locations, each of which can be defined uniquely by an address having an X component and a Y component. The locations correspond respectively to grid points in a rectangular array at a pitch dX in the X direction and a pitch dY in the Y direction is loaded with data values at locations corresponding to grid points lying substantially on a line from a location (X.sub.0 +e*dX, Y.sub.0 +f*dY) to a location (X.sub.0 +p*dX, Y.sub.0 +q*dY), where X.sub.0, Y.sub.0) is a grid point and e, f, p, and q are integers. The memory device is loaded by a method which includes(a) setting s=floor (p/q)______________________________________ PInc = p - sq -q NInc = p -sq AErr.sub.0 = PInc ______________________________________(b) for each value of i in the range from 0 to q-1, executing ______________________________________ If AErr.sub.i >= 0 then X.sub.i+i : = X.sub.i + (s + 1)dX AErr.sub.i+1 : = AErr.sub.i + PInc else X.sub.i+1 : = X.sub.i + sdX AErr.sub.

Abstract: An improved graphics display system includes a picture processor for processing display lists defining graphic designs, the display lists comprising pixel data and/or instructions for generating pixel data. The system further includes a display controller which stores pixel data in a frame buffer memory and controls a display of graphic designs in accordance therewith. When a display list defining a graphic design is changed but the design is not to be displayed, the display list is processed by the picture processor, but the output pixel data generated by the picture processor is routed not to the display controller but to a control processor which stores the generated pixel data in a second memory. When the design is thereafter to be displayed, the control processor generates a secondary display list including the pixel data stored in the second memory to the picture processor.

Abstract: Method and apparatus for drawing vectors on limited precision display devices in amounts of time approximately proportional to the vector's geometric length. Vectors are drawn by a series of strokes. Each stroke is a series of counter control signals, each signal representing a vertical, horizontal, or diagonal movement of the CRT electron beam between adjacent addressable screen points. The counter control signals making up the strokes are stored on a look-up table.

Abstract: In system and method for smooth line raster-scan display, a frame buffer containing a high resolution map of information of an image for display is read so as to furnish plural line stored information for each single line of the raster display. Display circuitry of the system receives the plural line stored information and varyingly weights same to furnish such single line Z-axis information (intensity control) for an X-Y display matrix, such as a CRT display terminal. Means are included in the system for display of the entire frame buffer content on a first fractional basis, e.g., a two thousand line resolution buffer to five hundred line raster. Selection circuitry of the system provides for reading out only a fraction of the frame buffer content, e.g., one-fourth or the five hundred lines thereof, on five hundred raster lines, thus providing true resolution zoom capability.

Abstract: A graphics display terminal is disclosed having a capability of responding to at least two unique input commands. A first assigns a segment to a group of classes and also removes the segment from membership in another group of classes. A second is a matching condition which requests that all the segments lying within a certain group of classes and/or not lying within another group of classes be identified, the CRT terminal highlighting these identified segments in response to a command from the operator. The second command is called a matching condition. Once all of the segments in a memory are located, which satisfy the matching condition, the operator can direct the terminal to blink or otherwise highlight the identified segments retrieved from memory.

Abstract: A high speed arrangement for generating smooth lines of consistent thickness regardless of slope in a raster type display system such as a computer graphics system. A digital differential analyzer is employed for determining Y-position information to n bits of fraction for each integral step in X within a single operative clock cycle. All pixel positions are identified that are relevantly proximate to the starting end point of the line, to the concluding end point, and each one-dimensional array of at least three contiguous pixel positions encompassing a cross-section of the interior portion of the line. Intensity values are determined for each such identified pixel position based upon its distance from the true line, with the intensities of the pixel positions identified in each array being additionally determined based upon the slope of the line.