Triangle.swift

import UIKit

@IBDesignable class Triangle: UIView {
    
    @IBInspectable var color: UIColor = .red
    @IBInspectable var firstPointX: CGFloat = 0
    @IBInspectable var firstPointY: CGFloat = 0
    @IBInspectable var secondPointX: CGFloat = 0.5
    @IBInspectable var secondPointY: CGFloat = 1
    @IBInspectable var thirdPointX: CGFloat = 1
    @IBInspectable var thirdPointY: CGFloat = 0

    override func draw(_ rect: CGRect) {
        let aPath = UIBezierPath()
        aPath.move(to: CGPoint(x: self.firstPointX * rect.width, y: self.firstPointY * rect.height))
        aPath.addLine(to: CGPoint(x: self.secondPointX * rect.width, y: self.secondPointY * rect.height))
        aPath.addLine(to: CGPoint(x: self.thirdPointX * rect.width, y: self.thirdPointY * rect.height))
        aPath.close()
        self.color.set()
        self.backgroundColor = .clear
        aPath.fill()
    }

}