ninjaprox/NVActivityIndicatorView

//
//  NVActivityIndicatorAnimationBallTrianglePath.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 NVActivityIndicatorAnimationBallTrianglePath: NVActivityIndicatorAnimationDelegate {

    func setUpAnimation(in layer: CALayer, size: CGSize, color: UIColor) {
        let circleSize = size.width / 5
        let deltaX = size.width / 2 - circleSize / 2
        let deltaY = size.height / 2 - circleSize / 2
        let x = (layer.bounds.size.width - size.width) / 2
        let y = (layer.bounds.size.height - size.height) / 2
        let duration: CFTimeInterval = 2
        let timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)

        // Animation
        let animation = CAKeyframeAnimation(keyPath: "transform")

        animation.keyTimes = [0, 0.33, 0.66, 1]
        animation.timingFunctions = [timingFunction, timingFunction, timingFunction]
        animation.duration = duration
        animation.repeatCount = HUGE
        animation.isRemovedOnCompletion = false

        // Top-center circle
        let topCenterCircle = NVActivityIndicatorShape.ring.layerWith(size: CGSize(width: circleSize, height: circleSize), color: color)

        changeAnimation(animation, values: ["{0,0}", "{hx,fy}", "{-hx,fy}", "{0,0}"], deltaX: deltaX, deltaY: deltaY)
        topCenterCircle.frame = CGRect(x: x + size.width / 2 - circleSize / 2, y: y, width: circleSize, height: circleSize)
        topCenterCircle.add(animation, forKey: "animation")
        layer.addSublayer(topCenterCircle)

        // Bottom-left circle
        let bottomLeftCircle = NVActivityIndicatorShape.ring.layerWith(size: CGSize(width: circleSize, height: circleSize), color: color)

        changeAnimation(animation, values: ["{0,0}", "{hx,-fy}", "{fx,0}", "{0,0}"], deltaX: deltaX, deltaY: deltaY)
        bottomLeftCircle.frame = CGRect(x: x, y: y + size.height - circleSize, width: circleSize, height: circleSize)
        bottomLeftCircle.add(animation, forKey: "animation")
        layer.addSublayer(bottomLeftCircle)

        // Bottom-right circle
        let bottomRightCircle = NVActivityIndicatorShape.ring.layerWith(size: CGSize(width: circleSize, height: circleSize), color: color)

        changeAnimation(animation, values: ["{0,0}", "{-fx,0}", "{-hx,-fy}", "{0,0}"], deltaX: deltaX, deltaY: deltaY)
        bottomRightCircle.frame = CGRect(x: x + size.width - circleSize, y: y + size.height - circleSize, width: circleSize, height: circleSize)
        bottomRightCircle.add(animation, forKey: "animation")
        layer.addSublayer(bottomRightCircle)
    }

    func changeAnimation(_ animation: CAKeyframeAnimation, values rawValues: [String], deltaX: CGFloat, deltaY: CGFloat) {
        let values = NSMutableArray(capacity: 5)

        for rawValue in rawValues {
            let point = NSCoder.cgPoint(for: translateString(rawValue, deltaX: deltaX, deltaY: deltaY))

            values.add(NSValue(caTransform3D: CATransform3DMakeTranslation(point.x, point.y, 0)))
        }
        animation.values = values as [AnyObject]
    }

    func translateString(_ valueString: String, deltaX: CGFloat, deltaY: CGFloat) -> String {
        let valueMutableString = NSMutableString(string: valueString)
        let fullDeltaX = 2 * deltaX
        let fullDeltaY = 2 * deltaY
        var range = NSRange(location: 0, length: valueMutableString.length)

        valueMutableString.replaceOccurrences(of: "hx", with: "\(deltaX)", options: NSString.CompareOptions.caseInsensitive, range: range)
        range.length = valueMutableString.length
        valueMutableString.replaceOccurrences(of: "fx", with: "\(fullDeltaX)", options: NSString.CompareOptions.caseInsensitive, range: range)
        range.length = valueMutableString.length
        valueMutableString.replaceOccurrences(of: "hy", with: "\(deltaY)", options: NSString.CompareOptions.caseInsensitive, range: range)
        range.length = valueMutableString.length
        valueMutableString.replaceOccurrences(of: "fy", with: "\(fullDeltaY)", options: NSString.CompareOptions.caseInsensitive, range: range)

        return valueMutableString as String
    }
}
#endif