Name

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CIRCLE

Purpose

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This function returns the x- and y- coordinates of a circle.

Category

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Graphics

Calling Sequence

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Result = CIRCLE( Xcentre, Ycentre, $
Radius, $
Npoints )

Inputs

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Xcentre: The x-coordinate of the circle's centre, of type
floating point.
Ycentre: The y-coordinate of the circle's centre, of type
floating point.
Radius: The radius of the circle, of type floating point.

Optional Inputs

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Npoints: The number of points to be defined on the circle,
of type integer. The default is 100.

Keyword Parameters

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OVERLAP: If set, the "ends" of the circle overlap. This produces
better results if plotting the circles with thick lines.

Outputs

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Result: Returns the x- and y- coordinates of the circle in
a 2*Npoints array.

Procedure

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This function calculates Npoints evenly-spaced points along a
circle.

Example

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Define a circle of unit radius centred on the origin.
result = circle( 0, 0, 5 )

Modification History

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  Written by: Edward C. Wiebe, 1997-12-10.
Modified by: Daithi A. Stone (stoned@atm.ox.ac.uk), 2000-07-05
(added Npoints optional input).
Modified by: DAS, 2004-11-26 (added OVERLAP keyword)