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Arc


Unit: SDL_rchart
Class: TRChart
Declaration: procedure Arc (cx, cy, HorizAxLeng, VertAxLeng, Angle1, Angle2: double);

The method Arc draws an arc along the perimeter of an ellipse. The center of the ellipse is specified by the parameters (cx,cy ), the length of the horizontal and vertical half axes is specified by HorizAxLeng and VertAxLeng, respectively. The arc is drawn counterclockwise from Angle1 to Angle2, the angles have to be specified in radians and may assume values between -pi and +pi. Angle values beyond this range will be automatically restricted.

The color of the boundary is determined by the property DataColor. The line width may be adjusted by the property LineWidth.

Hint 1: A circular arc can be drawn by setting HorizAxLeng and VertAxLeng to equal values (= radius of the circle). Please note that the actual appearance depends on the scaling of the chart axes, unless the property Isometric is set to TRUE.

Hint 2: You should avoid drawing arcs on a logarithmic chart, since the arc is not adjusted to the logarithmic coordinate system.

Hint 3: The angles of the arc are restricted in resolution to 0.001 arc seconds (approx. 8 decimal places) because the arc is encoded internally by integer values.



Last Update: 2016-Jun-26