add Shadow on UIView using swift 3

Question

prior swift 3 i was adding shadow in my UIView like this :

//toolbar is an UIToolbar (UIView) toolbar.layer.masksToBounds = false toolbar.layer.shadowOffset = CGSize(width: -1, height: 1) toolbar.layer.shadowRadius = 1 toolbar.layer.shadowOpacity = 0.5 

but the above code is not working in swift 3 , instead of shadow my whole View's color is turned to ugly gray

anyone knows how can we add shadow in swift 3 ?

Answer 1

CODE SNIPPET:

extension UIView {    // OUTPUT 1   func dropShadow(scale: Bool = true) {     layer.masksToBounds = false     layer.shadowColor = UIColor.black.cgColor     layer.shadowOpacity = 0.5     layer.shadowOffset = CGSize(width: -1, height: 1)     layer.shadowRadius = 1      layer.shadowPath = UIBezierPath(rect: bounds).cgPath     layer.shouldRasterize = true     layer.rasterizationScale = scale ? UIScreen.main.scale : 1   }    // OUTPUT 2   func dropShadow(color: UIColor, opacity: Float = 0.5, offSet: CGSize, radius: CGFloat = 1, scale: Bool = true) {     layer.masksToBounds = false     layer.shadowColor = color.cgColor     layer.shadowOpacity = opacity     layer.shadowOffset = offSet     layer.shadowRadius = radius      layer.shadowPath = UIBezierPath(rect: self.bounds).cgPath     layer.shouldRasterize = true     layer.rasterizationScale = scale ? UIScreen.main.scale : 1   } } 

NOTE: If you don't pass any parameter to that function, then the scale argument will be true by default. You can define a default value for any parameter in a function by assigning a value to the parameter after that parameter’s type. If a default value is defined, you can omit that parameter when calling the function.

OUTPUT 1:

shadowView.dropShadow() 

OUTPUT 2:

shadowView.dropShadow(color: .red, opacity: 1, offSet: CGSize(width: -1, height: 1), radius: 3, scale: true) 

layer.shouldRasterize = true will make the shadow static and cause a shadow for the initial state of the UIView. So I would recommend not to use layer.shouldRasterize = true in dynamic layouts like view inside a UITableViewCell.

Answer 2

Shadow using UIView Extension Swift 4

I would like to add one more line with selected answer! When we rasterizing the layer, It needs to be set to 2.0 for retina displays. Otherwise label text or images on that view will be blurry. So we need to add rasterizationScale also.

  extension UIView {      func dropShadow() {         layer.masksToBounds = false         layer.shadowColor = UIColor.black.cgColor         layer.shadowOpacity = 0.5         layer.shadowOffset = CGSize(width: -1, height: 1)         layer.shadowRadius = 1         layer.shadowPath = UIBezierPath(rect: self.bounds).cgPath         layer.shouldRasterize = true         layer.rasterizationScale = UIScreen.main.scale     } }