# addRelativeArc(center:radius:startAngle:delta:transform:) Adds an arc of a circle to the path, specified with a radius and a difference in angle. ``` func addRelativeArc(center: CGPoint, radius: CGFloat, startAngle: CGFloat, delta: CGFloat, transform: CGAffineTransform = .identity) ``` ## Parameters `center` The center of the arc, in user space coordinates. `radius` The radius of the arc, in user space coordinates. `startAngle` The angle to the starting point of the arc, measured in radians from the positive x-axis. `delta` The difference, measured in radians, between the starting angle and ending angle of the arc. A positive value creates a counter-clockwise arc (in user space coordinates), and vice versa. `transform` An affine transform to apply to the arc before adding to the path. Defaults to the identity transform if not specified. ## Discussion This method calculates starting and ending points using the radius and angles you specify, uses a sequence of cubic Bézier curves to approximate a segment of a circle between those points, and then appends those curves to the path. The `delta` parameter determines both the length of the arc the direction in which the arc is created; the actual direction of the final path is dependent on the transform parameter and the current transform of a context where the path is drawn. In a flipped coordinate system (the default for UIView drawing methods in iOS), specifying a clockwise arc results in a counterclockwise arc after the transformation is applied. If the path already contains a subpath, this method adds a line connecting the current point to the starting point of the arc. If the current path is empty, this method creates a new subpath whose starting point is the starting point of the arc. The ending point of the arc becomes the new current point of the path. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)