Function

Adds an arc of a circle to the current path, possibly preceded by a straight line segment

## 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.

### Constructing Paths

`CGContextAddArcToPoint`

Adds an arc of a circle to the current path, using a radius and tangent points.

`CGContextAddCurveToPoint`

Appends a cubic Bézier curve from the current point, using the provided control points and end point .

`CGContextAddLines`

Adds a sequence of connected straight-line segments to the current path.

`CGContextAddLineToPoint`

Appends a straight line segment from the current point to the provided point .

`CGContextAddPath`

Adds a previously created path object to the current path in a graphics context.

`CGContextCopyPath`

Returns a path object built from the current path information in a graphics context.

`CGContextAddQuadCurveToPoint`

Appends a quadratic Bézier curve from the current point, using a control point and an end point you specify.

`CGContextAddRect`

Adds a rectangular path to the current path.

`CGContextAddRects`

Adds a set of rectangular paths to the current path.

`CGContextBeginPath`

Creates a new empty path in a graphics context.

`CGContextClosePath`

Closes and terminates the current path’s subpath.

`CGContextMoveToPoint`

Begins a new subpath at the point you specify.

`CGContextAddEllipseInRect`

Adds an ellipse that fits inside the specified rectangle.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.