# CGContextAddArc Adds an arc of a circle to the current path, possibly preceded by a straight line segment ``` extern void CGContextAddArc(CGContextRef c, CGFloat x, CGFloat y, CGFloat radius, CGFloat startAngle, CGFloat endAngle, int clockwise); ``` ## Parameters `c` A graphics context. `x` The x-value, in user space coordinates, for the center of the arc. `y` The y-value, in user space coordinates, for the center of the arc. `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. `endAngle` The angle to the end point of the arc, measured in radians from the positive x-axis. `clockwise` Specify `1` to create a clockwise arc or `0` to create a counterclockwise arc. ## 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 current path. The clockwise parameter determines the direction in which the arc is created; the actual direction of the final path is dependent on the current transformation matrix of the graphics context. 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 current 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, his 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)