ninjaprox/NVActivityIndicatorView

//
//  NVActivityIndicatorAnimationCircleStrokeSpin.swift
//  NVActivityIndicatorView
//
// The MIT License (MIT)

// Copyright (c) 2016 Vinh Nguyen

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//

#if canImport(UIKit)
import UIKit

class NVActivityIndicatorAnimationCircleStrokeSpin: NVActivityIndicatorAnimationDelegate {

    func setUpAnimation(in layer: CALayer, size: CGSize, color: UIColor) {
        let beginTime: Double = 0.5
        let strokeStartDuration: Double = 1.2
        let strokeEndDuration: Double = 0.7

        let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation")
        rotationAnimation.byValue = Float.pi * 2
        rotationAnimation.timingFunction = CAMediaTimingFunction(name: .linear)

        let strokeEndAnimation = CABasicAnimation(keyPath: "strokeEnd")
        strokeEndAnimation.duration = strokeEndDuration
        strokeEndAnimation.timingFunction = CAMediaTimingFunction(controlPoints: 0.4, 0.0, 0.2, 1.0)
        strokeEndAnimation.fromValue = 0
        strokeEndAnimation.toValue = 1

        let strokeStartAnimation = CABasicAnimation(keyPath: "strokeStart")
        strokeStartAnimation.duration = strokeStartDuration
        strokeStartAnimation.timingFunction = CAMediaTimingFunction(controlPoints: 0.4, 0.0, 0.2, 1.0)
        strokeStartAnimation.fromValue = 0
        strokeStartAnimation.toValue = 1
        strokeStartAnimation.beginTime = beginTime

        let groupAnimation = CAAnimationGroup()
        groupAnimation.animations = [rotationAnimation, strokeEndAnimation, strokeStartAnimation]
        groupAnimation.duration = strokeStartDuration + beginTime
        groupAnimation.repeatCount = .infinity
        groupAnimation.isRemovedOnCompletion = false
        groupAnimation.fillMode = .forwards

        let circle = NVActivityIndicatorShape.stroke.layerWith(size: size, color: color)
        let frame = CGRect(
            x: (layer.bounds.width - size.width) / 2,
            y: (layer.bounds.height - size.height) / 2,
            width: size.width,
            height: size.height
        )

        circle.frame = frame
        circle.add(groupAnimation, forKey: "animation")
        layer.addSublayer(circle)
    }
}
#endif