VS:ThreePtCenter: Difference between revisions

Latest revision as of 06:13, 27 January 2022

.VectorScript|VectorScript ..VS:Function Reference|Function Reference ..VS:Function_Reference_Appendix|Appendix

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 ) 

    c = vs.ThreePtCenter( p1, p2, p3 )
    vs.Locus( c )

    t = vs.Perp( p2[0] - c[0], p2[1] - c[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

@@ Line 5: / Line 5: @@
 -----------------------------------------------------------------------------------------------------------
 <desc>
-Returns the center of a circle passing thru 3 given points.
+Returns the center of a circle passing thru 3 given points.</desc>
-</desc>
 -----------------------------------------------------------------------------------------------------------
 <def>
 <funcDef lang="vs">
-FUNCTION ThreePtCenter(pt1X, pt1Y, pt1Z :REAL; pt2X, pt2Y, pt2Z :REAL; pt3X, pt3Y, pt3Z :REAL) X, Y, Z :REAL;
+FUNCTION ThreePtCenter(pt1:VECTOR; pt2:VECTOR; pt3:VECTOR) : VECTOR;
 </funcDef>
 <funcDef lang="py">
@@ Line 23: / Line 22: @@
 <lineList ident=1>
 <line>
-pt1X, pt1Y, pt1Z
+pt1
-REAL
+VECTOR
 </line>
 <line>
-pt2X, pt2Y, pt2Z
+pt2
-REAL
+VECTOR
 </line>
 <line>
-pt3X, pt3Y, pt3Z
+pt3
-REAL
+VECTOR
 </line>
 </lineList>
 </params>
------------------------------------------------------------------------------------------------------------
-<return>
-</return>
 -----------------------------------------------------------------------------------------------------------
 <remark>
-([[User:Orso.b.schmid|Orso]], 2011 Jan. 08) This call never sets the z-value of the returned center: the z is always zero.
+([[User:CBM-c-|_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).
 </remark>
 -----------------------------------------------------------------------------------------------------------
 <sample>
+==== VectorScript ====
 <code lang="pas">
+{ finds the tangent angle between two poly sides }
 PROCEDURE Example;
 VAR
-   pt1, pt2, pt3, center_pt :VECTOR;
+    polyObj : HANDLE;
+    p1, p2, p3, c, t : VECTOR;
+    ang : REAL;
 BEGIN
-   GetPt(pt1.x, pt1.y);
+polyObj := FSActLayer; { take care to have a polygon selected }
-   GetPtL(pt1.x, pt1.y, pt2.x, pt2.y);
+IF polyObj <> NIL THEN BEGIN { not checking here for obj type, but you should }
-   MoveTo(pt1.x, pt1.y);
+    GetPolyPt( polyObj, 1, p1.x, p1.y );
-   LineTo(pt2.x, pt2.y);
+    GetPolyPt( polyObj, 2, p2.x, p2.y );
-   GetPtL(pt2.x, pt2.y, pt3.x, pt3.y);
+    GetPolyPt( polyObj, 3, p3.x, p3.y );
-   LineTo(pt3.x, pt3.y);
-   center_pt := ThreePtCenter(pt1, pt2, pt3);
+    c := ThreePtCenter( p1, p2, p3 );
-   Locus(center_pt.x, center_pt.y);
+    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);</code>
+Run(Example);
+</code>
+==== Python ====
+<code lang="py">
+# 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 )
+    c = vs.ThreePtCenter( p1, p2, p3 )
+    vs.Locus( c )
+    t = vs.Perp( p2[0] - c[0], p2[1] - c[1], 0 )
+    ang = vs.Vec2Ang( t )
+    vs.AlrtDialog( f'Angle of tangent at pt2:\r{ang:.3f}' ) # precision = 3, coercing float
+</code>
 </sample>
+-----------------------------------------------------------------------------------------------------------
+<seeAlso></seeAlso>
 -----------------------------------------------------------------------------------------------------------
 <version>
-Availability: from All Versions
+Availability: from Vectorworks 2014
-This is drop-in function.
 </version>
------------------------------------------------------------------------------------------------------------
-<seeAlso>
-</seeAlso>
 </vwDoc>