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Edit_Elliptical_Arc


Functions

void Edit_Elliptical_Arc (HC_KEY key, const HC_POINT *center, const HC_POINT *major, const HC_POINT *minor, double start, double end)

Function Documentation

void Edit_Elliptical_Arc ( HC_KEY  key,
const HC_POINT *  center,
const HC_POINT *  major,
const HC_POINT *  minor,
double  start,
double  end 
)

Edits an elliptical arc as it sits in the database.

Parameters:
key - Key to an elliptical arc object.
center - An x-y-z triplet for the coordinates of the center of an ellipse. (A simple array of three elements may also be used in most languages.) Passed by reference always.
major - An x-y-z triplet for the coordinates of the intersection of the ellipse and its major axis. Passed by reference always.
minor - An x-y-z triplet for the coordinates of the intersection of the ellipse and its minor axis. Passed by reference always.
start - The normalized parametric angle along the ellipse's perimeter, in the direction from the major to minor axis, where the arc starts.
end - The normalized parametric angle along the perimeter, in the direction from the major to minor axis, where the arc ends.

DETAILS

Elliptical arcs are grouped with lines, polylines, and circular arcs for rendering purposes. The rendition of an arc can be altered through the use of Line Color, Line Weight and Line Pattern. An ellipse's Visibility and Selectability can be controlled by the "line" or "polyline" keywords.

The direction of the perimeter is determined by the shortest path between the points used to define the major and minor axes. The starting and ending points are the parametric angular distances, specified between 0.0 and 1.0, along the perimeter. For example, a quarter of an ellipse could be specified with start and end points of 0.25 and 0.5, respectively.

NOTES

If you only work in two dimensions, specify all the z coordinates as zero. The system will automatically take note.

Make sure the points are not colinear. The system checks and issues an error message if all three points lie on a line, or if two points are coincident.

See also:
Insert_Elliptical_Arc, Insert_Ellipse, Insert_Circle, Insert_Circular_Arc, Insert_Polyline, Set_Line_Pattern, Set_Line_Weight, Set_Color, Renumber_Key.

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