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Pseudo Calligraphic Display on Discrete Display Devices

IP.com Disclosure Number: IPCOM000081440D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 36K

Publishing Venue

IBM

Related People

Giannuzzi, RJ: AUTHOR [+3]

Abstract

Information for graphic display is frequently, properly, and efficiently represented in vector form. Traditional graphic display devices are designed to match this kind of vector information representation by, in fact, displaying vectors. A present direction in display technology is directed toward representing vectors and other graphic elements by discretely addressed dots. Examples of such technology include gas panels, matrix printers, and conventional raster scanned cathode-ray tube (CRT) devices. The problem addressed by this description is that of converting a vector representation into a discrete dot representation in an acceptable and economic manner. Traditional Approaches.

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Pseudo Calligraphic Display on Discrete Display Devices

Information for graphic display is frequently, properly, and efficiently represented in vector form. Traditional graphic display devices are designed to match this kind of vector information representation by, in fact, displaying vectors. A present direction in display technology is directed toward representing vectors and other graphic elements by discretely addressed dots. Examples of such technology include gas panels, matrix printers, and conventional raster scanned cathode-ray tube (CRT) devices. The problem addressed by this description is that of converting a vector representation into a discrete dot representation in an acceptable and economic manner. Traditional Approaches.

The so-called "Bit-per-Element" approach employs a store capable of storing a bit for each picture element (dot) desired in the final output. In this store is generated an "image map" by considering each vector in turn, and setting each of the bits in the store that correspond to dots which will represent that vector. This approach requires exceptionally large capacity stores for such a display device. For example, a display with 512x512 addressable dots would require a store with a capacity of 262, 144 bits (i.e., 32K bytes).

The so-called "realtime" approach requires that each vector to be displayed be converted into a sequence of addresses of the picture elements that will make up that vector. Addresses for all of the dots for all of the vectors are sorted in scan order. These addresses are held in a store while the picture is scanned. When a scan position corresponds to an address held in the store, a picture element is written. This approach trades off storage capacity for processing and storage performance. Although the storage capacity has been reduced, it is still high since there must be enough capacity to hold the addresses of all of the picture elements that represent all of the vectors. In addition, the processing and storage performance requirements become severe.

The present approach occupies middle ground between these two approaches. It too trades off storage required by requiring more processing, but the processing performance requirements are not as severe as with the "realtime" approach. The Windowing Approach.

The approach described in the context where storage requirements for picture element mapping should be minimized, depends on the line-by-line scan characteristic...