Line circle with shadow swift

Question

I created line circle with shadow, but when I tried to change shadowRadius, the shadow was not showing

let path = UIBezierPath(ovalIn: rect)
let shapeLayer              = CAShapeLayer()
shapeLayer.path             = path.cgPath
shapeLayer.fillColor        = UIColor.clear.cgColor
shapeLayer.strokeColor      = UIColor.white.cgColor
shapeLayer.lineWidth        = 1
shapeLayer.shadowOpacity    = 0.9
shapeLayer.shadowColor      = UIColor.white.cgColor
shapeLayer.shadowOffset     = .zero
shapeLayer.shadowRadius     = 10.0
//shapeLayer.shadowPath       = path.cgPath

layer.addSublayer(shapeLayer)

line circle with default corner radius

line circle with corner radius 10.0

Can someone help me?

Answer 1

If you want to create the effect off a "stronger" shadow, you can do so by using a shadow path that has been stroked to be larger than the path that's "casting the shadow". This can be achieved using copy(strokingWithWidth:lineCap:lineJoin:miterLimit:transform:):

shapeLayer.shadowPath = path.cgPath.copy(strokingWithWidth: width, lineCap: .round, lineJoin: .round, miterLimit: 0)

This is what such a shadow (in red) looks like, both with and without any blur (shadow radius):

You can configure the shadowBlur and the width of the stroked shadow path to achieve the effect that you're after. Below are some examples: