Changing MapViewPort to MapViewProxy (maplibre#65)

* changing MapViewPort to MapViewProxy

* ran swiftformat

* annotation test as mainactor

Author: hactar

Sources/MapLibreSwiftUI/MapView.swift

@@ -16,7 +16,7 @@ public struct MapView<T: MapViewHostViewController>: UIViewControllerRepresentab
     var gestures = [MapGesture]()
 
     var onStyleLoaded: ((MLNStyle) -> Void)?
-    var onViewPortChanged: ((MapViewPort) -> Void)?
+    var onViewProxyChanged: ((MapViewProxy) -> Void)?
 
     var mapViewContentInset: UIEdgeInsets?
 
@@ -50,7 +50,7 @@ public struct MapView<T: MapViewHostViewController>: UIViewControllerRepresentab
         MapViewCoordinator<T>(
             parent: self,
             onGesture: { processGesture($0, $1) },
-            onViewPortChanged: { onViewPortChanged?($0) }
+            onViewProxyChanged: { onViewProxyChanged?($0) }
         )
     }
 

Sources/MapLibreSwiftUI/MapViewCoordinator.swift

@@ -20,15 +20,15 @@ public class MapViewCoordinator<T: MapViewHostViewController>: NSObject, MLNMapV
 
     var onStyleLoaded: ((MLNStyle) -> Void)?
     var onGesture: (MLNMapView, UIGestureRecognizer) -> Void
-    var onViewPortChanged: (MapViewPort) -> Void
+    var onViewProxyChanged: (MapViewProxy) -> Void
 
     init(parent: MapView<T>,
          onGesture: @escaping (MLNMapView, UIGestureRecognizer) -> Void,
-         onViewPortChanged: @escaping (MapViewPort) -> Void)
+         onViewProxyChanged: @escaping (MapViewProxy) -> Void)
     {
         self.parent = parent
         self.onGesture = onGesture
-        self.onViewPortChanged = onViewPortChanged
+        self.onViewProxyChanged = onViewProxyChanged
     }
 
     // MARK: Core UIView Functionality
@@ -366,7 +366,7 @@ public class MapViewCoordinator<T: MapViewHostViewController>: NSObject, MLNMapV
     public func mapView(_ mapView: MLNMapView, regionDidChangeWith reason: MLNCameraChangeReason, animated _: Bool) {
         // TODO: We could put this in regionIsChangingWith if we calculate significant change/debounce.
         MainActor.assumeIsolated {
-            updateViewPort(mapView: mapView, reason: reason)
+            updateViewProxy(mapView: mapView, reason: reason)
 
             guard !suppressCameraUpdatePropagation else {
                 return
@@ -376,17 +376,13 @@ public class MapViewCoordinator<T: MapViewHostViewController>: NSObject, MLNMapV
         }
     }
 
-    // MARK: MapViewPort
+    // MARK: MapViewProxy
 
-    @MainActor private func updateViewPort(mapView: MLNMapView, reason: MLNCameraChangeReason) {
-        // Calculate the Raw "ViewPort"
-        let calculatedViewPort = MapViewPort(
-            center: mapView.centerCoordinate,
-            zoom: mapView.zoomLevel,
-            direction: mapView.direction,
-            lastReasonForChange: CameraChangeReason(reason)
-        )
+    @MainActor private func updateViewProxy(mapView: MLNMapView, reason: MLNCameraChangeReason) {
+        // Calculate the Raw "ViewProxy"
+        let calculatedViewProxy = MapViewProxy(mapView: mapView,
+                                               lastReasonForChange: CameraChangeReason(reason))
 
-        onViewPortChanged(calculatedViewPort)
+        onViewProxyChanged(calculatedViewProxy)
     }
 }

Sources/MapLibreSwiftUI/MapViewModifiers.swift

@@ -130,9 +130,9 @@ public extension MapView {
         return result
     }
 
-    func onMapViewPortUpdate(_ onViewPortChanged: @escaping (MapViewPort) -> Void) -> Self {
+    func onMapViewProxyUpdate(_ onViewProxyChanged: @escaping (MapViewProxy) -> Void) -> Self {
         var result = self
-        result.onViewPortChanged = onViewPortChanged
+        result.onViewProxyChanged = onViewProxyChanged
         return result
     }
 

Sources/MapLibreSwiftUI/Models/MapCamera/CameraChangeReason.swift

@@ -1,6 +1,7 @@
 import Foundation
 import MapLibre
 
+@MainActor
 public enum CameraChangeReason: Hashable {
     case programmatic
     case resetNorth

Sources/MapLibreSwiftUI/Models/MapViewPort.swift

@@ -0,0 +1,73 @@
+import CoreLocation
+import Foundation
+import MapLibre
+
+/// A read only representation of the MapView's current View.
+///
+/// Provides access to properties and functions of the underlying MLNMapView,
+/// but properties only expose their getter, and functions are only available if they
+/// do no change the state of the MLNMapView. Writing directly to properties of MLNMapView
+/// could clash with swiftui-dsl's state management, which is why modifiying functions
+/// and properties are not exposed.
+///
+/// You can use `MapView.onMapViewProxyUpdate(_ onViewProxyChanged: @escaping (MapViewProxy) -> Void)` to
+/// recieve access to the MapViewProxy.
+///
+/// For more information about the properties and functions, see
+/// https://maplibre.org/maplibre-native/ios/latest/documentation/maplibre/mlnmapview
+@MainActor
+public struct MapViewProxy: Hashable, Equatable {
+    /// The current center coordinate of the MapView
+    public var centerCoordinate: CLLocationCoordinate2D {
+        mapView.centerCoordinate
+    }
+
+    /// The current zoom value of the MapView
+    public var zoomLevel: Double {
+        mapView.zoomLevel
+    }
+
+    /// The current compass direction of the MapView
+    public var direction: CLLocationDirection {
+        mapView.direction
+    }
+
+    public var visibleCoordinateBounds: MLNCoordinateBounds {
+        mapView.visibleCoordinateBounds
+    }
+
+    public var mapViewSize: CGSize {
+        mapView.frame.size
+    }
+
+    public var contentInset: UIEdgeInsets {
+        mapView.contentInset
+    }
+
+    /// The reason the view port was changed.
+    public let lastReasonForChange: CameraChangeReason?
+
+    private let mapView: MLNMapView
+
+    public func convert(_ coordinate: CLLocationCoordinate2D, toPointTo: UIView?) -> CGPoint {
+        mapView.convert(coordinate, toPointTo: toPointTo)
+    }
+
+    public init(mapView: MLNMapView,
+                lastReasonForChange: CameraChangeReason?)
+    {
+        self.mapView = mapView
+        self.lastReasonForChange = lastReasonForChange
+    }
+}
+
+public extension MapViewProxy {
+    /// Generate a basic MapViewCamera that represents the MapView
+    ///
+    /// - Returns: The calculated MapViewCamera
+    func asMapViewCamera() -> MapViewCamera {
+        .center(centerCoordinate,
+                zoom: zoomLevel,
+                direction: direction)
+    }
+}

Sources/MapLibreSwiftUI/Models/MapViewProxy.swift

@@ -15,7 +15,7 @@ final class MapViewCoordinatorCameraTests: XCTestCase {
         mapView = MapView(styleURL: URL(string: "https://maplibre.org")!)
         coordinator = MapView.Coordinator(parent: mapView) { _, _ in
             // No action
-        } onViewPortChanged: { _ in
+        } onViewProxyChanged: { _ in
             // No action
         }
     }

Tests/MapLibreSwiftUITests/MapViewCoordinator/MapViewCoordinatorCameraTests.swift

@@ -2,6 +2,7 @@ import MapLibre
 import XCTest
 @testable import MapLibreSwiftUI
 
+@MainActor
 final class CameraChangeReasonTests: XCTestCase {
     func testProgrammatic() {
         let mlnReason: MLNCameraChangeReason = [.programmatic]