Swift - Most code-efficient way to reuse gradients? - ios

Question

My UI calls for about 7-10 different gradients.
I have the first (default) gradient set up as followed:
let gradientLayer = CAGradientLayer()
And in my viewDidLoad:
gradientLayer.frame = self.view.bounds
gradientLayer.colors = [lightBlue, lightPurple]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.zPosition = -1
self.view.layer.addSublayer(gradientLayer)
gradientLayer is the default gradient. so let's say I want to define:
gradientVariantOne / gradientVariantTwo / gradientVariantThree (etc.)
but ALL of these new gradients will have the exact frame / locations / zPosition as gradientLayer.
How can I write my code so that these new gradients inherit those properties? This will keep the code much leaner, and easy to modify in the future.
Thank you

Answer 1

Actually I don't see what is gained by inheritance here. Just encapsulate the setting of the frame, locations, and zPosition into a method:
extension CAGradientLayer {
func configure(view:UIView) {
self.frame = view.bounds
self.locations = [0.0, 1.0]
self.zPosition = -1
}
}
Now you can just call configure to get the configuration of each gradient layer started. You could even add more parameters to configure (such as the colors array) and turn the whole thing into a one-liner:
extension CAGradientLayer {
func configure(view:UIView, colors:[CGColor]) {
self.frame = view.bounds
self.locations = [0.0, 1.0]
self.zPosition = -1
self.colors = colors
}
}
Thus a single call to configure configures the whole layer and you're done.

Answer 2

You can create a UIView extension and add your gradients by calling a method.
extension UIView {
private func prepareGradient() -> CAGradientLayer {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = self.bounds
//add all common setup here
return gradientLayer
}
func addGradientVariantOne() {
let gradientLayer = prepareGradient()
gradientLayer.colors = [lightBlue, lightPurple]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.zPosition = -1
self.layer.addSublayer(gradientLayer)
}
}
Then you can simply call:
self.view.addGradientVariantOne()
Just create a similar function for each gradient.