How do I cast two shadows from an UIImageView with a SF Symbol as the image? - swift

Question

I want to cast a shadow to the lower left AND the lower right of my Image. But I'm struggling to get the second shadow cast (layer2)...
I've created a subclass of UIImage view and use that in IB:
import UIKit
class ShadowImageView: UIImageView {
var layer2 = CALayer()
override func layoutSubviews() {
super.layoutSubviews()
self.layer2 = CALayer(layer: self.layer)
self.clipsToBounds = false
self.layer.shadowColor = UIColor.gray.cgColor
self.layer.shadowOffset = CGSize(width: -16, height: 16)
self.layer.shadowOpacity = 0.33
self.layer.shadowRadius = 3
self.layer.masksToBounds = false
self.layer2.shadowColor = UIColor.gray.cgColor
self.layer2.shadowOffset = CGSize(width: 16, height: 16)
self.layer2.shadowOpacity = 0.33
self.layer2.shadowRadius = 3
self.layer2.masksToBounds = false
self.layer.insertSublayer(self.layer2, at: 0)
print("\(self.layer)\n")
if let sublayers = self.layer.sublayers {
for layer in sublayers {
print("\(layer)\n")
}
}
}
}
Am I going in the right direction to copy the layer and apply a new shadow to it or should I look in a different direction?

Answer 1

Fixed the shadow problem. I was able to generate double shadows by adding 3 layers on my UIView. The furthest behind (the first sublayer of the view's layer) is the darker shadow, the one on top of that is the lighter shadow and on top of that I have one with the normal color.
I'm 'drawing' the images on the layers by applying a shadow path & color.
The image I'm drawing is coming from a method like listed below, but it's not being generated from a SFSymbols. I would like to generate it during runtime so I end up with a simple method of using symbols to place Neumorphic elements in our apps. The manual generation of these BezierPaths isn't really pleasant.
static var shieldFill: UIBezierPath = {
let bezierPath = UIBezierPath()
bezierPath.move(to: CGPoint(x: 58.94, y: 115.53))
bezierPath.addCurve(to: CGPoint(x: 62.84, y: 114.4), controlPoint1: CGPoint(x: 60.06, y: 115.53), controlPoint2: CGPoint(x: 61.57, y: 115.04))
bezierPath.addCurve(to: CGPoint(x: 101.76, y: 74.46), controlPoint1: CGPoint(x: 91.5, y: 100.49), controlPoint2: CGPoint(x: 101.76, y: 91.89))
bezierPath.addLine(to: CGPoint(x: 101.76, y: 39.94))
bezierPath.addCurve(to: CGPoint(x: 92.04, y: 25.05), controlPoint1: CGPoint(x: 101.76, y: 31.84), controlPoint2: CGPoint(x: 99.41, y: 28.12))
bezierPath.addCurve(to: CGPoint(x: 67.63, y: 16.85), controlPoint1: CGPoint(x: 87.89, y: 23.29), controlPoint2: CGPoint(x: 71.29, y: 17.97))
bezierPath.addCurve(to: CGPoint(x: 58.94, y: 15.53), controlPoint1: CGPoint(x: 64.94, y: 16.11), controlPoint2: CGPoint(x: 61.52, y: 15.53))
bezierPath.addCurve(to: CGPoint(x: 50.24, y: 16.85), controlPoint1: CGPoint(x: 56.35, y: 15.53), controlPoint2: CGPoint(x: 52.93, y: 16.11))
bezierPath.addCurve(to: CGPoint(x: 25.83, y: 25.05), controlPoint1: CGPoint(x: 46.53, y: 17.97), controlPoint2: CGPoint(x: 29.93, y: 23.29))
bezierPath.addCurve(to: CGPoint(x: 16.11, y: 39.94), controlPoint1: CGPoint(x: 18.46, y: 28.12), controlPoint2: CGPoint(x: 16.11, y: 31.84))
bezierPath.addLine(to: CGPoint(x: 16.11, y: 74.46))
bezierPath.addCurve(to: CGPoint(x: 55.03, y: 114.4), controlPoint1: CGPoint(x: 16.11, y: 91.89), controlPoint2: CGPoint(x: 26.46, y: 100.29))
bezierPath.addCurve(to: CGPoint(x: 58.94, y: 115.53), controlPoint1: CGPoint(x: 56.3, y: 115.04), controlPoint2: CGPoint(x: 57.76, y: 115.53))
bezierPath.close()
return bezierPath
}()

Answer 2

I was able to get this very easily:
That seems to be the sort of thing you're after.
The double shadow stems from the fact that in a graphics context, shadow drawing is a state applied to any future drawing. So if you set the context's shadow to be down-and-to-the-left and draw the symbol image, and then set the context's shadow to be down-and-to-the-right and draw the symbol image, you get the double shadow.
It is true that the symbol image itself is drawn twice but that does not necessarily change the way it appears; if I hadn't told you I'd drawn it twice, I don't think you'd have known.