CGAffineTransformRotate(_:_:)
Returns an affine transformation matrix constructed by rotating an existing affine transform.
Declaration
func CGAffineTransformRotate(_ t: CGAffineTransform, _ angle: CGFloat) -> CGAffineTransformParameters
- t:
An existing affine transform.
- angle:
The angle, in radians, by which to rotate the affine transform. In iOS, a positive value specifies counterclockwise rotation and a negative value specifies clockwise rotation. In macOS, a positive value specifies clockwise rotation and a negative value specifies counterclockwise rotation.
Return Value
A new affine transformation matrix.
Discussion
You use this function to create a new affine transformation matrix by adding a rotation value to an existing affine transform. The resulting structure represents a new affine transform, which you can use (and reuse, if you want) to rotate a coordinate system.
The actual direction of rotation is dependent on the coordinate system orientation of the target platform, which is different in iOS and macOS.