UIKit Motion / Shadow Effects Helper

ParallaxShaderViewExtension.swift

import UIKit
import Foundation

extension UIView {
    
    /// Adds a shadow to the layer of a view.
    func addShadow(color: UIColor = .black,
                   opacity: Float = 0.4,
                   radius: Float = 3.0,
                   offset: CGSize = CGSize(width:0, height:2)
    ) {
        self.layer.shadowColor = color.cgColor
        self.layer.shadowOpacity = opacity
        self.layer.shadowRadius = CGFloat(radius)
        self.layer.shadowOffset = offset
    }

    /// Applies a UIInterpolationMotionEffect on the layer's shadowOffset
    func addShadowParallaxMotionEffect(amount: Float) {
        let motionX = UIInterpolatingMotionEffect(keyPath: "layer.shadowOffset.width", type: UIInterpolatingMotionEffect.EffectType.tiltAlongHorizontalAxis)
        let motionY = UIInterpolatingMotionEffect(keyPath: "later.shadowOffset.height", type: UIInterpolatingMotionEffect.EffectType.tiltAlongVerticalAxis)
        motionX.maximumRelativeValue = amount
        motionX.minimumRelativeValue = -amount
        motionY.maximumRelativeValue = amount
        motionY.minimumRelativeValue = -amount
        let group = UIMotionEffectGroup()
        group.motionEffects = [motionX, motionY]
        self.addMotionEffect(group)
    }
    
   /// Applies a UIInterpolationMotionEffect on the view's center.
    func addParallaxMotionEffect(amount: Float) {
        let motionX = UIInterpolatingMotionEffect(keyPath: "center.x", type: UIInterpolatingMotionEffect.EffectType.tiltAlongHorizontalAxis)
        let motionY = UIInterpolatingMotionEffect(keyPath: "center.y", type: UIInterpolatingMotionEffect.EffectType.tiltAlongVerticalAxis)
        motionX.maximumRelativeValue = CGFloat(amount)
        motionX.minimumRelativeValue = CGFloat(-amount)
        motionY.maximumRelativeValue = CGFloat(amount)
        motionY.minimumRelativeValue = CGFloat(-amount)
        let group = UIMotionEffectGroup()
        group.motionEffects = [motionX, motionY]
        self.addMotionEffect(group)
    }
    
    func addParallaxAndShadowEffects(amount: Float) {
        self.addShadow()
        self.addShadowParallaxMotionEffect(amount: amount)
        self.addParallaxMotionEffect(amount: amount)
    }
  
    func addParallaxAndShadowEffects(motionParallaxAmount: Float, shadowParallaxAmount: Float) {
        self.addShadow()
        self.addParallaxMotionEffect(amount: motionParallaxAmount)
        self.addShadowParallaxMotionEffect(amount: shadowParallaxAmount)
    }
}