Swift Arrowhead using CGPath

gistfile1.txt

// Arrowhead pointing in the direction of "towards" CGPoint - supports triangular, pointy and diamond shaped heads as well
//
// Based on https://gist.github.com/mayoff/4146780//
//

import UIKit

class ArrowHeadPath {
        
    class func create(from start: CGPoint, towards end: CGPoint,  width: CGFloat, headLengthOuter: CGFloat, headLengthInner: CGFloat) -> CGPath {
        let length = hypot(end.x - start.x, end.y - start.y)
        
        func p(_ x: CGFloat, _ y: CGFloat) -> CGPoint { return CGPoint(x: x, y: y) }
        var points: [CGPoint] = [
            p(headLengthOuter - headLengthInner , 0),
            p(0, width / 2),
            p(headLengthOuter, 0),
            p(0, -width / 2),
            ]
        
        let cosine = (end.x - start.x) / length
        let sine = (end.y - start.y) / length
        var transform = CGAffineTransform(a: cosine, b: sine, c: -sine, d: cosine, tx: start.x, ty: start.y)
        
        let path = CGMutablePath()
        path.addLines(between: points, transform: transform)
        path.closeSubpath()        
        return path
    }
    
}