Draws Linear Gradient and designable from storyboard.

DesignableGradientView.swift

import Foundation
import Cocoa

// MARK: - Abstract
/// Draws Linear Gradient and designable from storyboard.

class DesignableGradientView: NSView {
   
    @IBInspectable var isDrawGradient: Bool = false {
        didSet {
            reDrawGradient()
        }
    }
    
    @IBInspectable open var startColor: NSColor = .init(red: 0.86, green: 0.25, blue: 0.59, alpha: 1) {
        didSet {
            reDrawGradient()
        }
    }
    @IBInspectable open var endColor: NSColor = .init(red: 0.11, green: 0.14, blue: 0.46, alpha: 0.86) {
        didSet {
            reDrawGradient()
        }
    }
    @IBInspectable open var rotation: CGFloat = 45.0 {
        didSet{
            reDrawGradient()
        }
    }
    @IBInspectable open var startPosition: CGFloat = .zero {
        didSet{
            reDrawGradient()
        }
    }
    @IBInspectable open var endPosition: CGFloat = 1.0 {
        didSet{
            reDrawGradient()
        }
    }
    
    override open func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
       
        guard isDrawGradient else {
            return
        }
        let bgGradient = NSGradient.init(colorsAndLocations: (startColor, startPosition), (endColor, endPosition))
        bgGradient?.draw(in: dirtyRect, angle: rotation)
          
    }
    
    func reDrawGradient() {
        needsDisplay = true
    }
}