Modulation function in Swift

modulate.swift

// let value = Modulate(1, from: [0, 10], to: [0, 20], true);
// print(value); 
// Returns 2

func Modulate(_ input: Float, from: [Float], to: [Float], limit: Bool) -> Float {
    let result = to[0] + (((input - from[0]) / (from[1] - from[0])) * (to[1] - to[0]));

    if (limit) {
        if (to[0] < to[1]) {
            if (result < to[0]) { return to[0] }
            if (result > to[1]) { return to[1] }
        }
        else {
            if (result > to[0]) { return to[0] }
            if (result < to[1]) { return to[1] }
        }
    }

    return result
}

I noticed this is actually the same way how FramerJS does.
But this can be more simplified in Swift.
To deal with UIView animations like CGAffineTransform better use CGFloat instead.

extension CGFloat {
    func modulate(from: [CGFloat], to: [CGFloat], limit: Bool) -> CGFloat {
        let result = to[0] + (((self - from[0]) / (from[1] - from[0])) * (to[1] - to[0]))
        return limit ? [[result, to.min()!].max()!, to.max()!].min()! : result
    }
}



CGFloat(5.0).modulate(from: [0, 10], to: [0, 100], limit: true)       // 50
CGFloat(20.0).modulate(from: [0, 10], to: [0, 100], limit: true)      // 100
CGFloat(15.0).modulate(from: [10, 20], to: [20, 40], limit: true)     // 30
CGFloat(75.0).modulate(from: [100, 50], to: [200, 100], limit: true)  // 150
CGFloat(200.0).modulate(from: [100, 0], to: [200, 100], limit: false) // 300