Swift make UIView border into Gradient Color - swift

Question

I want to create a gradient border on a UIView.
The following code can produce a solid for the view Box1.
nothing I have found allows me to change the frameColor to a gradient.
var frameColor = UIColor.red.cgColor
var leftBorder = CALayer()
leftBorder.frame = CGRect(x: 0.0, y: 0, width: 1, height: box1.frame.size.height )
leftBorder.backgroundColor = frameColor
I am using Swift 5 and Xcode 11.
Thank you.

Answer 1

Try with below extension
public extension UIView {
private static let kLayerNameGradientBorder = "GradientBorderLayer"
func setGradientBorder(
width: CGFloat,
colors: [UIColor],
startPoint: CGPoint = CGPoint(x: 0.5, y: 0),
endPoint: CGPoint = CGPoint(x: 0.5, y: 1)
) {
let existedBorder = gradientBorderLayer()
let border = existedBorder ?? CAGradientLayer()
border.frame = bounds
border.colors = colors.map { return $0.cgColor }
border.startPoint = startPoint
border.endPoint = endPoint
let mask = CAShapeLayer()
mask.path = UIBezierPath(roundedRect: bounds, cornerRadius: 0).cgPath
mask.fillColor = UIColor.clear.cgColor
mask.strokeColor = UIColor.white.cgColor
mask.lineWidth = width
border.mask = mask
let exists = existedBorder != nil
if !exists {
layer.addSublayer(border)
}
}
func removeGradientBorder() {
self.gradientBorderLayer()?.removeFromSuperlayer()
}
private func gradientBorderLayer() -> CAGradientLayer? {
let borderLayers = layer.sublayers?.filter { return $0.name == UIView.kLayerNameGradientBorder }
if borderLayers?.count ?? 0 > 1 {
fatalError()
}
return borderLayers?.first as? CAGradientLayer
}
}
Usage
self.borderView.setGradientBorder(width: 5.0, colors: [UIColor.red , UIColor.blue])
I hope this will reach your requirement.
https://medium.com/#kushal0409/gradient-button-3dc8ef763039

Answer 2

There is no off-the-shelf way to do this, but you could build it yourself.
Off the top of my head, the approach might look like this:
Create a CAGradientLayer and set it up to draw your gradient as
desired.
Create a CAShapeLayer that contains an empty rectangle that is your
frame.
Add your shape layer as the mask of your gradient layer.
Add the gradient layer to your view as a sub-layer of the view's
content layer.

Answer 3

Swift 5 extension (works with corner radius)
extension UIView {
func gradientBorder(colors: [UIColor], isVertical: Bool){
self.layer.masksToBounds = true
//Create gradient layer
let gradient = CAGradientLayer()
gradient.frame = CGRect(origin: CGPoint.zero, size: self.bounds.size)
gradient.colors = colors.map({ (color) -> CGColor in
color.cgColor
})
//Set gradient direction
if(isVertical){
gradient.startPoint = CGPoint(x: 0.5, y: 0)
gradient.endPoint = CGPoint(x: 0.5, y: 1)
}
else {
gradient.startPoint = CGPoint(x: 0, y: 0.5)
gradient.endPoint = CGPoint(x: 1, y: 0.5)
}
//Create shape layer
let shape = CAShapeLayer()
shape.lineWidth = 1
shape.path = UIBezierPath(roundedRect: gradient.frame.insetBy(dx: 1, dy: 1), cornerRadius: self.layer.cornerRadius).cgPath
shape.strokeColor = UIColor.black.cgColor
shape.fillColor = UIColor.clear.cgColor
gradient.mask = shape
//Add layer to view
self.layer.addSublayer(gradient)
gradient.zPosition = 0
}
}