Browse Prior Art Database

Vector Graphics on a Raster Display

IP.com Disclosure Number: IPCOM000083797D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Evans, PJ: AUTHOR

Abstract

A modification of the system shown is provided whereby more vectors per raster line can be handled, although at the cost of increased flicker perceptibility. The number of vectors displayed as crossing a single raster line is limited by the speed of the vector generator relative to the line period. A typical number is 128 vectors. It is proposed that additional vectors be displayed on the next frame, instead of the vectors displayed on the first frame.

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Vector Graphics on a Raster Display

A modification of the system shown is provided whereby more vectors per raster line can be handled, although at the cost of increased flicker perceptibility. The number of vectors displayed as crossing a single raster line is limited by the speed of the vector generator relative to the line period. A typical number is 128 vectors. It is proposed that additional vectors be displayed on the next frame, instead of the vectors displayed on the first frame.

In the illustrated system, coded graphic data is supplied by host processor 1 to refresh buffer 2. Data relating to each entity about to be displayed is passed to intermediate buffer 3 from which it is transferred, as appropriate, to vector generator 4 or symbol generator 5. The generators 4, 5, feed a partial raster assembly store 6 which holds, for example, two raster lines of video information.

Refresh buffer 2 holds an index of pointers, one for each raster line. The pointer is used to address the first new vector to be used in generation of the raster line. Each vector has a next address field which points to the next vector. The last vector of a line addresses the index pointer of the next line.

According to the modification a secondary list is provided with a pointer for each line. At the end of every line period, the secondary pointer for a line is loaded with either the address of the pointer for the next line if all vectors have been processed, or the address of the nex...