[ios, macos] Hook up hillshade style layers, raster DEM sources to iOS/macOS (#11036)

* [ios, macos] Finished implementing MGLHillshadeStyleLayer

* [macos] Added icon for hillshade layer

Also set the background layer icon to mirror in right-to-left locales.

* [ios, macos] Implemented raster DEM source

* [macos] Added Enhance Terrain debugging command

* [ios, macos] Simplified raster DEM source example

3 files changed, 48 insertions, 19 deletions

diff --git a/platform/darwin/test/MGLDocumentationExampleTests.swift b/platform/darwin/test/MGLDocumentationExampleTests.swift
index d3e2bf91f2..9bf9924869 100644
--- a/platform/darwin/test/MGLDocumentationExampleTests.swift
+++ b/platform/darwin/test/MGLDocumentationExampleTests.swift
@@ -88,6 +88,26 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
 
         XCTAssertNotNil(mapView.style?.source(withIdentifier: "clouds"))
     }
+    
+    func testMGLRasterDEMSource() {
+        // We want to use mapbox.terrain-rgb in the example, but using a mapbox:
+        // URL requires setting an access token. So this identically named
+        // subclass of MGLRasterDEMSource swaps in a nonexistent URL.
+        class MGLRasterDEMSource: Mapbox.MGLRasterDEMSource {
+            override init(identifier: String, configurationURL: URL, tileSize: CGFloat = 256) {
+                let bogusURL = URL(string: "https://example.com/raster-rgb.json")!
+                super.init(identifier: identifier, configurationURL: bogusURL, tileSize: tileSize)
+            }
+        }
+        
+        //#-example-code
+        let terrainRGBURL = URL(string: "mapbox://mapbox.terrain-rgb")!
+        let source = MGLRasterDEMSource(identifier: "hills", configurationURL: terrainRGBURL)
+        mapView.style?.addSource(source)
+        //#-end-example-code
+        
+        XCTAssertNotNil(mapView.style?.source(withIdentifier: "hills"))
+    }
 
     func testMGLVectorSource() {
         //#-example-code
@@ -256,6 +276,33 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
         XCTAssertNotNil(mapView.style?.layer(withIdentifier: "clouds"))
     }
 
+    func testMGLHillshadeStyleLayer() {
+        let source = MGLRasterDEMSource(identifier: "dem", tileURLTemplates: ["https://example.com/raster-rgb/{z}/{x}/{y}.png"], options: [
+            .minimumZoomLevel: 9,
+            .maximumZoomLevel: 16,
+            .tileSize: 256,
+            .attributionInfos: [
+                MGLAttributionInfo(title: NSAttributedString(string: "© Mapbox"), url: URL(string: "http://mapbox.com"))
+            ]
+        ])
+        mapView.style?.addSource(source)
+        
+        let canals = MGLVectorSource(identifier: "canals", configurationURL: URL(string: "https://example.com/style.json")!)
+        mapView.style?.addSource(canals)
+        let canalShadowLayer = MGLLineStyleLayer(identifier: "waterway-river-canal-shadow", source: canals)
+        mapView.style?.addLayer(canalShadowLayer)
+
+        //#-example-code
+        let layer = MGLHillshadeStyleLayer(identifier: "hills", source: source)
+        layer.hillshadeExaggeration = NSExpression(forConstantValue: 0.6)
+        if let canalShadowLayer = mapView.style?.layer(withIdentifier: "waterway-river-canal-shadow") {
+            mapView.style?.insertLayer(layer, below: canalShadowLayer)
+        }
+        //#-end-example-code
+
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "hills"))
+    }
+
     func testMGLVectorStyleLayer$predicate() {
         let terrain = MGLVectorSource(identifier: "terrain", configurationURL: URL(string: "https://example.com/style.json")!)
         mapView.style?.addSource(terrain)
diff --git a/platform/darwin/test/MGLHillshadeStyleLayerTests.mm b/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
index 8f37b52790..b0b7ddd5ee 100644
--- a/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
+++ b/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
@@ -18,24 +18,6 @@
     return @"hillshade";
 }
 
-- (void)testPredicates {
-    MGLPointFeature *feature = [[MGLPointFeature alloc] init];
-    MGLShapeSource *source = [[MGLShapeSource alloc] initWithIdentifier:@"sourceID" shape:feature options:nil];
-    MGLHillshadeStyleLayer *layer = [[MGLHillshadeStyleLayer alloc] initWithIdentifier:@"layerID" source:source];
-
-    XCTAssertNil(layer.sourceLayerIdentifier);
-    layer.sourceLayerIdentifier = @"layerID";
-    XCTAssertEqualObjects(layer.sourceLayerIdentifier, @"layerID");
-    layer.sourceLayerIdentifier = nil;
-    XCTAssertNil(layer.sourceLayerIdentifier);
-
-    XCTAssertNil(layer.predicate);
-    layer.predicate = [NSPredicate predicateWithValue:NO];
-    XCTAssertEqualObjects(layer.predicate, [NSPredicate predicateWithValue:NO]);
-    layer.predicate = nil;
-    XCTAssertNil(layer.predicate);
-}
-
 - (void)testProperties {
     MGLPointFeature *feature = [[MGLPointFeature alloc] init];
     MGLShapeSource *source = [[MGLShapeSource alloc] initWithIdentifier:@"sourceID" shape:feature options:nil];
diff --git a/platform/darwin/test/MGLStyleLayerTests.mm.ejs b/platform/darwin/test/MGLStyleLayerTests.mm.ejs
index 0487066255..e26c63e662 100644
--- a/platform/darwin/test/MGLStyleLayerTests.mm.ejs
+++ b/platform/darwin/test/MGLStyleLayerTests.mm.ejs
@@ -23,7 +23,7 @@
     return @"<%- type %>";
 }
 
-<% if (type !== 'background' && type !== 'raster') { -%>
+<% if (type !== 'background' && type !== 'raster' && type !== 'hillshade') { -%>
 - (void)testPredicates {
     MGLPointFeature *feature = [[MGLPointFeature alloc] init];
     MGLShapeSource *source = [[MGLShapeSource alloc] initWithIdentifier:@"sourceID" shape:feature options:nil];