Remove opacity and use alpha component

Example/ViewController.swift

@@ -17,12 +17,25 @@ class ViewController: UIViewController {
 
     override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
+
+        let coordinates = [CLLocationCoordinate2D(latitude: 45.4562, longitude: -122.8793),
+                           CLLocationCoordinate2D(latitude: 45.4562, longitude: -122.4645),
+                           CLLocationCoordinate2D(latitude: 45.6582, longitude: -122.4645),
+                           CLLocationCoordinate2D(latitude: 45.6582, longitude: -122.8793),
+                           CLLocationCoordinate2D(latitude: 45.4562, longitude: -122.8793)]
+
+        let path = Path(coordinates: coordinates)
+        path.fillColor = UIColor.red.withAlphaComponent(0.5)
+        path.strokeColor = UIColor.green.withAlphaComponent(0.5)
 
         let camera = SnapshotCamera(lookingAtCenter: CLLocationCoordinate2D(latitude: 45, longitude: -122), zoomLevel: 6)
         let options = SnapshotOptions(
             styleURL: URL(string: "mapbox://styles/mapbox/streets-v9")!,
             camera: camera,
             size: imageView.bounds.size)
+
+        options.overlays.append(path)
+
         _ = Snapshot(options: options, accessToken: accessToken).image { [weak self] (image, error) in
             if let error = error {
                 print(error)

MapboxStatic/Color.swift

@@ -27,6 +27,19 @@ internal extension Color {
 
         return NSString(format: "%02x%02x%02x", Int(r), Int(g), Int(b)) as String
     }
+
+    #if !os(macOS)
+    internal var alphaComponent: CGFloat {
+        var r: CGFloat = 0
+        var g: CGFloat = 0
+        var b: CGFloat = 0
+        var a: CGFloat = 0
+
+        getRed(&r, green: &g, blue: &b, alpha: &a)
+
+        return a
+    }
+    #endif
 
     convenience init(hexString: String) {
         var hexString = hexString.replacingOccurrences(of: "#", with: "")

MapboxStatic/Overlay.swift

@@ -328,20 +328,6 @@ open class Path: NSObject, Overlay {
     open var fillColor = UIColor(hexString: "555")
     #endif
 
-    /**
-     The stroke opacity of the overlay, expressed as a percentage such that 0.0 is completely transparent and 1.0 is completely opaque.
-
-     By default, the overlay’s stroke is completely opaque.
-     */
-    open var strokeOpacity: Double = 1
-
-    /**
-     The fill opacity of the overlay, expressed as a percentage such that 0.0 is completely transparent and 1.0 is completely opaque.
-
-     By default, the overlay’s fill is completely transparent.
-     */
-    open var fillOpacity: Double = 0
-
     /**
      Initializes a polyline overlay with the given vertices.
 
@@ -437,9 +423,9 @@ open class Path: NSObject, Overlay {
 
     open override var description: String {
         let encodedPolyline = polylineEncode(coordinates).addingPercentEncoding(withAllowedCharacters: allowedCharacterSet)!
-        var description = "path-\(strokeWidth)+\(strokeColor.toHexString())-\(strokeOpacity)"
-        if fillOpacity > 0 {
-            description += "+\(fillColor.toHexString())-\(fillOpacity)"
+        var description = "path-\(strokeWidth)+\(strokeColor.toHexString())-\(strokeColor.alphaComponent)"
+        if fillColor.alphaComponent > 0 {
+            description += "+\(fillColor.toHexString())-\(fillColor.alphaComponent)"
         }
         description += "(\(encodedPolyline))"
         return description

MapboxStaticTests/ClassicOverlayTests.swift

@@ -131,10 +131,8 @@ class ClassicOverlayTests: XCTestCase {
                 )
             ])
         path.strokeWidth = 2
-        path.strokeColor = .black
-        path.strokeOpacity = 0.75
-        path.fillColor = .red
-        path.fillOpacity = 0.25
+        path.strokeColor = Color.black.withAlphaComponent(0.75)
+        path.fillColor = Color.red.withAlphaComponent(0.25)
 
         let options = ClassicSnapshotOptions(
             mapIdentifiers: ["mapbox.streets"],