LocationDegreesFormatter.swift

gistfile1.txt

import CoreLocation

class LocationDegreesFormatter: Formatter {
    
    enum Direction {
        case none
        case latitude
        case longitude
    }
    
    enum Format {
        case degrees
        case degreesMinutes
        case degreesMinutesSeconds
    }
    
    var direction: Direction = .none
    var format: Format = .degreesMinutesSeconds
    var minimumFractionDigits = 1
    var maximumFractionDigits = 5 // accurate to 1.1132 meters
    
    lazy var degreesFormatter: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.locale = Locale.current
        formatter.numberStyle = .decimal
        formatter.minimumFractionDigits = minimumFractionDigits
        formatter.maximumFractionDigits = maximumFractionDigits
        return formatter
    }()
    
    lazy var minutesFormatter: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.locale = Locale.current
        formatter.numberStyle = .decimal
        formatter.minimumFractionDigits = 3
        formatter.maximumFractionDigits = 3
        formatter.paddingCharacter = "0"
        formatter.paddingPosition = .afterPrefix
        formatter.minimumIntegerDigits = 2
        formatter.maximumIntegerDigits = 2
        return formatter
    }()
    
    override func string(for obj: Any?) -> String? {
        guard let degrees = obj as? CLLocationDegrees else { return nil }
        return string(from: degrees)
    }
    
    func string(from: CLLocationDegrees) -> String? {
        var degrees = from
        
        var suffix: String?
        switch direction {
        case .none:
            break
        case .latitude:
            guard(-90.0...90.0).contains(degrees) else { return nil }
            suffix = degrees >= 0.0 ? "N" : "S"
            
        case .longitude:
            guard(-180.0...180.0).contains(degrees) else { return nil }
            suffix = degrees >= 0.0 ? "E" : "W"
        }
        
        if direction != .none { degrees = abs(degrees) }
        
        let minutes = (abs(degrees) * 60.0).truncatingRemainder(dividingBy: 60.0)
        let seconds = (abs(degrees) * 3600.0).truncatingRemainder(dividingBy: 60.0)
        
        var string = ""
        
        switch format {
        case .degrees:
            let degreesString = degreesFormatter.string(from: NSNumber(value: degrees)) ?? "\(degrees)"
            string = "\(degreesString)°"
        case .degreesMinutes:
            let minutesString = minutesFormatter.string(from: NSNumber(value: minutes)) ?? "\(minutes)"
            string = "\(Int(floor(degrees)))° \(minutesString)′"
        case .degreesMinutesSeconds:
            string = "\(Int(floor(degrees)))° \(Int(floor(minutes)))′ \(Int(round(seconds)))″"
        }
        
        if let suffix = suffix {
            string.append(" " + suffix)
        }
        
        return string
    }
    
    override func getObjectValue(_ obj: AutoreleasingUnsafeMutablePointer<AnyObject?>?, for string: String, errorDescription error: AutoreleasingUnsafeMutablePointer<NSString?>?) -> Bool {
        error?.pointee = "Not implemented"
        return false
    }
}