A system and method for generating properly proportioned alphanumeric characters and symbols in two vertical heights with a single character generator and a minimum of associated circuitry. The bits of video data stored in the character generator are stored such that the vertical segments of diagonal portions of the characters and symbols include no more than two bits per vertical segment of the diagonal portion. The video data bits representative of the pels of circular portions of the symbols ...

An image display system suitable for use in displaying, at an enlarged scale, any desired portion of an image presented on a picture surface of a display apparatus, or in displaying, in a reduced scale, the whole portion of the image presented on the picture surface. The picture surface is divided into sub-regions arranged in m lines and n columns. Sub-region appointing numeral keys are arranged to correspond to these sub-regions, so that any desired sub-region is appointed by a depression of th...

An image data conversion method for converting the image data signal to the runlength signal through the process for reading once or several times a runlength code from a runlength conversion table for a given image data signal and a process for adding the pertinent runlength code when the same type of runlength code appears continuously. A character code/character pattern conversion apparatus which uses said image data conversion method, and provides, moreover, a multiplication device for multi...

A dual mode raster scanned character display system has a text mode of operation in which characters having a first matrix size are displayed on a CRT screen and a high resolution mode of operation in which display information is bit mapped on the CRT screen. Programmable font characters are stored in a memory and are accessed by controller characters generated in response to display requests supplied by an associated information source, such as a computer or a keyboard. Each controller characte...

Image display apparatus reads data from an image memory to produce an image on a interlaced raster-scanned display. The image can be zoomed by producing X and Y magnifications. X magnification is produced by repeating each pixel a predetermined number of times. Y magnification is produced by repeating each display line a predetermined number of times. The number of repetitions of each display line can be varied from line to line and can be different in the two frames, so as to cope with odd-numb...

An image processing method for conducting a diversification processing on an original image. An image data written in a work area is shifted by a number corresponding to the amount of the diversification processing and the data obtained through shifting is logically processed to form a predetermined image data. Then, logical computation is conducted on the original image data written in another work area and the above-mentioned predetermined image data, whereby a diversification processing is co...

An improved method for displaying a character on a raster device at relatively low resolution by identifying regions of the character that improperly touch other regions of the character, and then modifying the display of that character to move or delete pixels which decrease legibility of the character, by (1) enumerating the pixels in an order determined by the path topology, (2) searching for sequences of pixels corresponding to a pointed feature in the character that undesirably touches othe...

Apparatus for modifying an alphanumeric display produced on a cathode-ray tube screen by raster scan to enable the selective generation of double height characters. In order to retain synchronism between line counters and the raster number modifiers are connected to the outputs of the counters to modify the addresses selected from a read only memory for generating the characters.

A video display terminal is disclosed for use in displaying images of data characters on a display screen. Multi-bit coded data words are supplied by a data source, such as a memory, to a character generator circuit which controls the display of data characters on the face of a video display screen. The coded data words generally fall into three categories; to wit, character codes, control codes and attribute codes. Character codes describe the type of character to be presented on the screen. At...

A system for localizing a region of a display incorporates a plurality of resettable counters for defining the position and extent of a cursor in two dimensions. Data is set into the counters periodically at the beginning of each frame, or at the beginning of each scanning line, so that the size and shape of the cursor is selectable, as well as its position on the display. When the data is modified during successive time periods, the cursor can be made to progressively reduce its size so as to i...