Instance Method

addCurve(to:controlPoint1:controlPoint2:)

Appends a cubic Bézier curve to the receiver’s path.

Declaration

func addCurve(to endPoint: CGPoint, controlPoint1: CGPoint, controlPoint2: CGPoint)

Parameters

endPoint

The end point of the curve.

controlPoint1

The first control point to use when computing the curve.

controlPoint2

The second control point to use when computing the curve.

Discussion

This method appends a cubic Bézier curve from the current point to the end point specified by the endPoint parameter. The two control points define the curvature of the segment. Figure 1 shows an approximation of a cubic Bézier curve given a set of initial points. The exact curvature of the segment involves a complex mathematical relationship between all of the points and is well documented online.

Figure 1

A cubic Bézier curve

You must set the path’s current point (using the move(to:) method or through the previous creation of a line or curve segment) before you call this method. If the path is empty, this method does nothing. After adding the curve segment, this method updates the current point to the value in point.