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Language for Defining Computer Graphics Generation

IP.com Disclosure Number: IPCOM000076557D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 18K

Publishing Venue

IBM

Related People

Tsui, K: AUTHOR [+2]

Abstract

A language especially efficient for defining the generation of computer graphics has been designed. A graphic figure is considered to consist of a series of contiguous, linear and curved segments which are defined by a series of description elements. (A figure containing disjoined parts is represented by a group of contiguous segments with the links being suppressed in the display). Each element describing a segment consists of 4 items, viz.

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Language for Defining Computer Graphics Generation

A language especially efficient for defining the generation of computer graphics has been designed. A graphic figure is considered to consist of a series of contiguous, linear and curved segments which are defined by a series of description elements. (A figure containing disjoined parts is represented by a group of contiguous segments with the links being suppressed in the display). Each element describing a segment consists of 4 items, viz., (B, C, A, L), where B is a "brightness bit" ("1" for display, "0" for suppression of display), C is a "circular-arc sense bit" (1 for clockwise, 0 for counterclockwise), A is the angular change associated with the segment, and L is the length of the segment, with A and L being expressed in units of alpha and lambda, which are the smallest resolvable fraction of 2 pi and of the size of the display panel, respectively. For example, for a system with a display panel of 512 x 512 points (lambda=1/512) and an angular resolution of 2tau/32 (alpha = 1/32), a group of 4 description elements (1, 1, 2, 32), (1, 1, 24, 28), (0, 0, 18, 0), and (1, 1, 24, 32), starting with an initial angle of 8 alpha(90 degrees), will suffice to define the Greek letter beta as shown in the figure.

The language has the following advantages: 1) A "rotate" operation on graphic figures is greatly simplified. All that is necessary is to add an element (O, O, Ar, O) preceding the description elements for the...