VS:ThreePtCenter
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Description
Returns the center of a circle passing thru 3 given points.
FUNCTION ThreePtCenter(
pt1 :VECTOR;
pt2 :VECTOR;
pt3 :VECTOR) : VECTOR;
def vs.ThreePtCenter(pt1, pt2, pt3): return VECTOR
Parameters
pt1 VECTOR pt2 VECTOR pt3 VECTOR
Remarks
(_c_, 2022.01.18) In VS Python this routine returns a 3-dimensional tuple. Warning: Most Math - Vector routines require a 3-dimensional tuple, failing to init a third item in VW before 2023 (vs.Vec2Ang, for example, returns gibberish on 2-d tuples).
Example
VectorScript
{ finds the tangent angle between two poly sides } PROCEDURE Example; VAR polyObj : HANDLE; p1, p2, p3, c, t : VECTOR; ang : REAL; BEGIN polyObj := FSActLayer; { take care to have a polygon selected } IF polyObj <> NIL THEN BEGIN { not checking here for obj type, but you should } GetPolyPt( polyObj, 1, p1.x, p1.y ); GetPolyPt( polyObj, 2, p2.x, p2.y ); GetPolyPt( polyObj, 3, p3.x, p3.y ); c := ThreePtCenter( p1, p2, p3 ); Locus( c.x, c.y ); t := Perp( p2 - c ); ang := Vec2Ang( t ); AlrtDialog( Concat('Angle of tangent at pt2: ', Chr(13), Num2Str(3, ang)) ); END; Run(Example);
Python
# finds the tangent angle between two poly sides polyObj = vs.FSActLayer() # take care to have a polygon selected if polyObj != vs.Handle( 0 ): # not checking here for obj type, but you should p1 = vs.GetPolyPt( polyObj, 1 ) p2 = vs.GetPolyPt( polyObj, 2 ) p3 = vs.GetPolyPt( polyObj, 3 ) cen = vs.ThreePtCenter( p1, p2, p3 ) vs.Locus( cen ) t = vs.Perp( p2[0] - cen[0], p2[1] - cen[1] ) # Perp always return a 3-dimensional tuple # if you don't use Perp, you might need to add a third item = 0, or Vec2Ang returns gibberish on VW before 2023 # example: v = ( p2[0] - cen[0], p2[1] - cen[1], 0 ) ang = vs.Vec2Ang( t ) vs.AlrtDialog( f'Angle of tangent at pt2:\r{ang:.3f}' ) # precision = 3, coercing float
Version
Availability: from Vectorworks 2014