A raster video display system utilizes memory capacity more efficiently than conventional raster display systems and is independent of the specific resolution of the screen which is utilized in the system. The raster display system comprises a VRAM with split transfer capability and a unique address generator which can determine when pixels from a particular row of the screen display start on one row of the VRAM and extend over to the next row of the VRAM.

A full page display device for a text processing system in which a text stream input by way of a keyboard is stored and displayed to the operator on a display device including a cathode ray tube, the electron beam of which is modulated and scanned in a series of horizontal traces to produce an image of the text line on the screen of the display device. The system comprises storage means which includes a plurality (four in a specific embodiment) of separate storage devices. In the specific embodi...

A logic control system for a video display terminal is disclosed for accommodating vertically and horizontally varying entry points to a video memory to acquire first character bytes of rows of video information for display on a CRT screen. Dynamically changeable display page snapshots of the video memory, and the formation of display pages from randomly located rows of video information within the video memory are thereby provided.

Electronic circuitry for generation of graphics images on a computer display screen is disclosed which allows graphics capability to be added or retrofitted to computers having standard video display character generation circuitry. The graphics circuitry receives address, data and control signals from the normal computer peripheral bus. Address signals received by the graphics circuitry are interpreted as command signals and, in accordance with the command signals, data present on the computer p...

This invention provides a method and apparatus for controlling the type of information displayed at each display pixel on the video monitor of a video display system. A number of video RAMs are provided which number is at least equal to the number of different types of information. A bitmap is stored for each type of information in the video RAMs in interspersed fashion, a selected number of bits for select display pixels of the bitmap for a given type of information being simultaneously stored ...

With a data display terminal having an electron beam tube, an image repetition memory serves for cyclically regenerating the display. With a change of the display, a complete overwriting can be necessary. However, the overwriting of the image repetition memory cannot interrupt the regeneration operation. The beam flyback times during an image cycle do not suffice in order to overwrite the entire image repetition memory. Therefore, data are written into the image repetition memory during a forwar...

A frame buffer memory capable of storing video data for plural frames of pictures with memory areas irrelevant to the display being reduced to a minimum, which video data consist of a number of pixels unequal to a power of "2" in the vertical and horizontal directions, respectively. The frame buffer memory is realized by using multi-port video RAMs and includes a plurality of regions for display and auxiliary regions. The regions for display includes at least first and second display regions whi...

There is disclosed a graphics display controller for controlling a display memory, which includes a display address register temporarily storing an address which is changed in a predetermined cycle during a display period, a first circuit for producing a first signal each time less significant bits of the address becomes the same value as each other, a second circuit for producing a second signal each time a horizontal scan line to be displayed changes, and a third circuit for producing a displa...

A system for using the page buffer memory which stores the pixel map to generate the cursor in a CRT display. An unused portion of the memory is used to store a duplicate copy of the band in which the cursor is currently located, and the cursor is written into its appropriate location in this duplicate band, thus destroying the underlying image in the duplicate, but not in the original. The display is then generated by cycling through the page buffer except that the duplicate band containing the...

A cursor generation circuit for an image display system that includes a storing circuit for storing image data. The storing circuit includes a first port to provide access to the image data to the display system and a second port to provide access to the image data to a display device for displaying the image data. A combining circuit is further provided to combine the image data with cursor data in the storing circuit when the storing circuit is being accessed by the display device. However, th...