Span

This object is the base class for spans in a Contour. Spans are either lines, arcs or beziers or a single ‘point’

Constructors

Span( Point3D pt3d)

A new span representing a single point is created within a Lua script using this constructor method

pt3d - Point3D - 3d position for a point

e.g

local pt = Point3D(0, 0, 0)

local pt_span = Span(pt)

NOTE: most spans are created as either a LineSpan, ArcSpan or BezierSpan.

Properties

.EndPoint3D

Interaction: Read Only

Returns: (Point3D) The 3D end point of the span  

.EndPoint2D

Interaction: Read Only

Returns: (Point2D)  The 2D end point of the span  

.IsLineType

Interaction: Read Only

Returns: (Bool) true if span is a line      

.IsArcType

Interaction: Read Only

Returns: (Bool)  true if span is an arc  

.IsBezierType

Interaction: Read Only

Returns: (Bool)  true if span is a bezier   

.IsLeadInType

Interaction: Read Only

Returns: (Bool) true if span is a lead in   

.IsLeadOutType

Interaction: Read Only

Returns: (Bool) true if span is a lead out   

.IsOvercutType

Interaction: Read Only

Returns: (Bool) true if span is part of an overcut  

.NumberOfControlPoints

Interaction: Read Only

Returns: (Integer) number of control points for span (2 for Bezier, 1 for an arc (the mid point), 0 for a line  

.StartPoint3D

Interaction: Read Only

Returns: (Point3D) The 3D start point of the span  

.StartPoint2D

Interaction: Read Only

Returns: (Point2D) The 2D start point of the span  

.Type

Interaction: Read Only

Returns: (Integer) enum identifying type of the span  

Usual values are Span.NormalLine, Span.Arc and Span.Bezier

Methods

:ChordLength()

Return the straight-line distance between start and end points of the span

:EndVector( bool normalise)

Return a Vector2D representing the direction of the span at the end.

normalise - bool - if true, the returned vector is normalised  

:GetControlPointPosition( integer index)

Return a Point2D with position of requested control point (use .NumberOfControlPoints to get count). This call is only valid on a Bezier or an Arc. For a Bezier 0 returns first control point, 1 returns the second. For an arc, 0 returns arc mid point.

index - integer - index of control point  

:GetLength( double tolerance)

Return a double holding the length of the span. The passed tolerance is used for beziers to approximate length to given tolerance.

tolerance - double - tolerance to use when polygonizing beziers to find length  

:MoveControlPoint( integer index, Point2D pt)

This is only valid for an arc or Bezier and attempts to move the specified control point to the passed position. This call is only valid on a Bezier or an Arc. For a Bezier, index 0 modifies first control point, 1 modifies the second. For an arc, 0 modifies the arc mid point. If the control point can’t be moved to the passed position (e.g would make an invalid arc) returns false, else true.

index - integer - index of control point pt - Point2D - position for control point  

:PointAtParameter( double param, double tolerance)

Return a Point2D representing the point on the span at passed parameter in range 0 - 1.0. Passed tolerance is used for polygonisation for Bezier spans.

parameter - double - parameter in range 0 - 1.0 to find point on span at tolerance - double - tolerance to use when polygonizing beziers :Reverse()

Reverse the span - swap start and end points and for arcs swap sign of bulge, for beziers swap control points.

:StartVector( bool normalise)

Return a Vector2D representing the direction of the span at the start.

normalise - bool - if true, the returned vector is normalized  

:SetStartPoint3D( Point3D pt)

Set start point for span - be EXTREMELY careful if you call this method on spans in a contour as gaps will open between adjoining spans leading to an invalid contour.

pt - Point3D - 3D position for point  

:SetStartPoint2D( Point2D pt)

Set start point for span - be EXTREMELY careful if you call this method on spans in a contour as gaps will open between adjoining spans leading to an invalid contour.

pt - Point2D - 2D position for point  

:SetEndPoint3D( Point3D pt)

Set end point for span - be EXTREMELY careful if you call this method on spans in a contour as gaps will open between adjoining spans leading to an invalid contour.

pt - Point3D - 3D position for point  

:SetEndPoint2D( Point2D pt)

Set end point for span - be EXTREMELY careful if you call this method on spans in a contour as gaps will open between adjoining spans leading to an invalid contour.

pt - Point2D - 2D position for point  

References

Please Note: The base material for the contents found in this WiKi was sourced from Vectric Lua Interface for Gadgets, version 2.05, published September 12, 2018. by Vectric Ltd. Most current document from Vertric can be downloaded at Vertric Developer Information