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The Drawing Primitives

Drawing primitives are the basic elements of graphics output, such as lines, text etc. GKS supports the six output primitives which are described below: polyline, polymarker, fill area, text, cell array, and the generalised drawing primitive. Each primitive has a corresponding set of attributes e.g. line type, colour index, character height, etc. The appearance of an individual primitive is governed by the attributes in force at the time when the primitive is passed to GKS, and attribute setting will be described in the following chapter. A number of example programs may be found in Appendix on Page gif which illustrate the use of the following features.



Figure: Examples of some GKS Primitives

The Polyline, Polymarker, and Fill Area primitives are specified by an array of points which may not be arbitrarily large, and the maximum size of this array is implementation-dependent. The GKSGRAL implementation at CERN restricts the number points in a Fill Area to 300. However, calls to Polyline or Polymarker can handle more points than this by internally sub-dividing the array.

Janne Saarela
Mon Apr 3 17:00:12 METDST 1995