[macos, ios] Insert layer above

include/mbgl/map/map.hpp

@@ -159,6 +159,7 @@ class Map : private util::noncopyable {
     // Layers
     style::Layer* getLayer(const std::string& layerID);
     void addLayer(std::unique_ptr<style::Layer>, const optional<std::string>& beforeLayerID = {});
+    void insertLayer(std::unique_ptr<style::Layer>, const std::string& afterLayerID);
     void removeLayer(const std::string& layerID);
 
     // Add image, bound to the style

platform/darwin/src/MGLStyle.h

@@ -208,6 +208,14 @@ static const NSInteger MGLStyleDefaultVersion = 9;
  */
 - (void)insertLayer:(MGLStyleLayer *)layer belowLayer:(MGLStyleLayer *)otherLayer;
 
+/**
+ Inserts a new layer above another layer.
+
+ @param layer Layer to be inserted.
+ @param aboveLayer A layer that's already on the map view.
+ */
+- (void)insertLayer:(MGLStyleLayer *)layer aboveLayer:(MGLStyleLayer *)otherLayer;
+
 /**
  Removes a layer from the map view.
 

platform/darwin/src/MGLStyle.mm

@@ -203,6 +203,27 @@ - (void)insertLayer:(MGLStyleLayer *)layer belowLayer:(MGLStyleLayer *)otherLaye
     self.mapView.mbglMap->addLayer(std::unique_ptr<mbgl::style::Layer>(layer.layer), belowLayerId);
 }
 
+- (void)insertLayer:(MGLStyleLayer *)layer aboveLayer:(MGLStyleLayer *)otherLayer
+{
+    if (!layer.layer) {
+        [NSException raise:NSInvalidArgumentException
+                    format:
+         @"The style layer %@ cannot be added to the style. "
+         @"Make sure the style layer was created as a member of a concrete subclass of MGLStyleLayer.",
+         NSStringFromClass(layer)];
+    }
+    if (!otherLayer.layer) {
+        [NSException raise:NSInvalidArgumentException
+                    format:
+         @"A style layer cannot be placed before %@ in the style. "
+         @"Make sure the style layer was created as a member of a concrete subclass of MGLStyleLayer.",
+         NSStringFromClass(otherLayer)];
+    }
+
+    auto afterLayerID = otherLayer.layer->getID();
+    self.mapView.mbglMap->insertLayer(std::unique_ptr<mbgl::style::Layer>(layer.layer), afterLayerID);
+}
+
 - (void)addSource:(MGLSource *)source
 {
     self.mapView.mbglMap->addSource(source.mbglSource);

platform/ios/app/MBXViewController.m

@@ -676,10 +676,26 @@ - (void)styleRoadLayer
     roadLayer.lineColor = roadLineColor;
     roadLayer.lineWidth = lineWidthFunction;
     roadLayer.lineGapWidth = lineWidthFunction;
+
+    MGLLineCap lineCap = MGLLineCapRound;
+    NSValue *lineCapValue = [NSValue value:&lineCap withObjCType:@encode(MGLLineCap)];
+    roadLayer.lineCap = [MGLStyleValue<NSValue *> valueWithRawValue:lineCapValue];
 
     roadLayer.visible = YES;
     roadLayer.maximumZoomLevel = 15;
     roadLayer.minimumZoomLevel = 13;
+
+    NSString *filePath = [[NSBundle bundleForClass:self.class] pathForResource:@"polyline" ofType:@"geojson"];
+    NSURL *geoJSONURL = [NSURL fileURLWithPath:filePath];
+    MGLGeoJSONSource *source = [[MGLGeoJSONSource alloc] initWithIdentifier:@"ams" URL:geoJSONURL options:nil];
+    [self.mapView.style addSource:source];
+
+    MGLLineStyleLayer *topMostLayer = (MGLLineStyleLayer *)[self.mapView.style layerWithIdentifier:@"road-trunk"];
+    MGLLineStyleLayer *insertLayer = [[MGLLineStyleLayer alloc] initWithIdentifier:@"testLayer" source:source];
+    insertLayer.lineColor = [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor greenColor]];
+    insertLayer.lineWidth = topMostLayer.lineWidth;
+
+    [self.mapView.style insertLayer:insertLayer aboveLayer:topMostLayer];
 }
 
 - (void)styleRasterLayer

src/mbgl/map/map.cpp

@@ -807,6 +807,20 @@ void Map::addLayer(std::unique_ptr<Layer> layer, const optional<std::string>& be
 
     impl->view.deactivate();
 }
+
+void Map::insertLayer(std::unique_ptr<Layer> layer, const std::string &after) {
+    if (!impl->style) {
+        return;
+    }
+
+    impl->styleMutated = true;
+    impl->view.activate();
+
+    impl->style->insertLayer(std::move(layer), after);
+    update(Update::Classes);
+
+    impl->view.deactivate();
+}
 
 void Map::removeLayer(const std::string& id) {
     if (!impl->style) {

src/mbgl/style/style.cpp

@@ -185,6 +185,31 @@ Layer* Style::addLayer(std::unique_ptr<Layer> layer, optional<std::string> befor
     return layers.emplace(before ? findLayer(*before) : layers.end(), std::move(layer))->get();
 }
 
+Layer* Style::insertLayer(std::unique_ptr<Layer> layer, const std::string &after) {
+
+    if (SymbolLayer* symbolLayer = layer->as<SymbolLayer>()) {
+        if (!symbolLayer->impl->spriteAtlas) {
+            symbolLayer->impl->spriteAtlas = spriteAtlas.get();
+        }
+    }
+
+    if (CustomLayer* customLayer = layer->as<CustomLayer>()) {
+        customLayer->impl->initialize();
+    }
+
+    layer->baseImpl->setObserver(this);
+
+    auto it = std::find_if(layers.begin(), layers.end(), [&](const auto& fl) {
+        return fl->baseImpl->id == after;
+    });
+
+    if (it != layers.end()) {
+        it++;
+    }
+
+    return layers.insert(it, std::move(layer))->get();
+}
+
 void Style::removeLayer(const std::string& id) {
     auto it = findLayer(id);
     if (it == layers.end())

src/mbgl/style/style.hpp

@@ -72,6 +72,8 @@ class Style : public GlyphAtlasObserver,
     Layer* getLayer(const std::string& id) const;
     Layer* addLayer(std::unique_ptr<Layer>,
                     optional<std::string> beforeLayerID = {});
+    Layer* insertLayer(std::unique_ptr<Layer>,
+                       const std::string& afterLayerID);
     void removeLayer(const std::string& layerID);
 
     std::string getName() const;

test/api/custom_layer.test.cpp

@@ -110,9 +110,16 @@ TEST(CustomLayer, Basic) {
         }, new TestLayer()));
 
     auto layer = std::make_unique<FillLayer>("landcover", "mapbox");
+    std::string layerID = layer->getID();
     layer->setSourceLayer("landcover");
     layer->setFillColor(Color{ 1.0, 1.0, 0.0, 1.0 });
     map.addLayer(std::move(layer));
 
+    auto insertLayer = std::make_unique<FillLayer>("landcover", "mapbox");
+    insertLayer->setSourceLayer("landcover");
+    insertLayer->setFillColor(Color{ 0.0, 0.0, 0.0, 0.0 });
+    insertLayer->setFillOutlineColor(Color{ 0.0, 0.0, 1, 1.0 });
+    map.insertLayer(std::move(insertLayer), layerID);
+
     test::checkImage("test/fixtures/custom_layer/basic", test::render(map), 0.0006, 0.1);
 }