CGPathAddRelativeArc
Appends an arc to a mutable graphics path, possibly preceded by a straight line segment.
Declaration
extern void CGPathAddRelativeArc(CGMutablePathRef path, const CGAffineTransform *matrix, CGFloat x, CGFloat y, CGFloat radius, CGFloat startAngle, CGFloat delta);Parameters
- path:
The mutable graphics path to change.
- matrix:
A pointer to an affine transformation matrix, or
NULLif no transformation is needed. If specified, Core Graphics applies the transformation to the arc before it is added to the path. - x:
The x-coordinate of the center point of the arc.
- y:
The y-coordinate of the center point of the arc.
- radius:
The radius of the arc.
- startAngle:
The angle (in radians) that determines the starting point of the arc, measured from the x-axis in the current user space.
- delta:
The distance the arc should travel (in radians). A positive value indicates a counter-clockwise arc in the current user space.
Discussion
The angle to the second endpoint of the arc is calculated by adding the delta to the start angle.