[core] Observe visibility changes

package.json

@@ -22,7 +22,7 @@
     "express": "^4.11.1",
     "mapbox-gl-shaders": "mapbox/mapbox-gl-shaders#de2ab007455aa2587c552694c68583f94c9f2747",
     "mapbox-gl-style-spec": "mapbox/mapbox-gl-style-spec#83b1a3e5837d785af582efd5ed1a212f2df6a4ae",
-    "mapbox-gl-test-suite": "mapbox/mapbox-gl-test-suite#ac0e1907ff628e662dafeb44cdab6e594b59a59b",
+    "mapbox-gl-test-suite": "mapbox/mapbox-gl-test-suite#5b2e5749e85ad4241b5b4e4e54d2fa98e8920f34",
     "mkdirp": "^0.5.1",
     "node-cmake": "^1.2.1",
     "request": "^2.72.0",

src/mbgl/style/layer.cpp

@@ -19,7 +19,10 @@ VisibilityType Layer::getVisibility() const {
 }
 
 void Layer::setVisibility(VisibilityType value) {
+    if (value == getVisibility())
+        return;
     baseImpl->visibility = value;
+    baseImpl->observer->onLayerVisibilityChanged(*this);
 }
 
 float Layer::getMinZoom() const {

src/mbgl/style/layer_observer.hpp

@@ -10,6 +10,7 @@ class LayerObserver {
     virtual ~LayerObserver() = default;
 
     virtual void onLayerFilterChanged(Layer&) {}
+    virtual void onLayerVisibilityChanged(Layer&) {}
     virtual void onLayerPaintPropertyChanged(Layer&) {}
     virtual void onLayerLayoutPropertyChanged(Layer&) {}
 };

src/mbgl/style/style.cpp

@@ -506,9 +506,11 @@ void Style::onSpriteError(std::exception_ptr error) {
 struct QueueSourceReloadVisitor {
     UpdateBatch& updateBatch;
 
-    void operator()(CustomLayer&) { assert(false); }
-    void operator()(RasterLayer&) { assert(false); }
-    void operator()(BackgroundLayer&) { assert(false); }
+    // No need to reload sources for these types; their visibility can change but
+    // they don't participate in layout.
+    void operator()(CustomLayer&) {}
+    void operator()(RasterLayer&) {}
+    void operator()(BackgroundLayer&) {}
 
     template <class VectorLayer>
     void operator()(VectorLayer& layer) {
@@ -521,6 +523,11 @@ void Style::onLayerFilterChanged(Layer& layer) {
     observer->onUpdate(Update::Layout);
 }
 
+void Style::onLayerVisibilityChanged(Layer& layer) {
+    layer.accept(QueueSourceReloadVisitor { updateBatch });
+    observer->onUpdate(Update::Layout);
+}
+
 void Style::onLayerPaintPropertyChanged(Layer&) {
     observer->onUpdate(Update::RecalculateStyle | Update::Classes);
 }

src/mbgl/style/style.hpp

@@ -136,6 +136,7 @@ class Style : public GlyphStoreObserver,
 
     // LayerObserver implementation.
     void onLayerFilterChanged(Layer&) override;
+    void onLayerVisibilityChanged(Layer&) override;
     void onLayerPaintPropertyChanged(Layer&) override;
     void onLayerLayoutPropertyChanged(Layer&) override;
 

test/src/mbgl/test/stub_layer_observer.hpp

@@ -14,6 +14,10 @@ class StubLayerObserver : public style::LayerObserver {
         if (layerFilterChanged) layerFilterChanged(layer);
     }
 
+    void onLayerVisibilityChanged(Layer& layer) override {
+        if (layerVisibilityChanged) layerVisibilityChanged(layer);
+    }
+
     void onLayerPaintPropertyChanged(Layer& layer) override {
         if (layerPaintPropertyChanged) layerPaintPropertyChanged(layer);
     }
@@ -23,6 +27,7 @@ class StubLayerObserver : public style::LayerObserver {
     }
 
     std::function<void (Layer&)> layerFilterChanged;
+    std::function<void (Layer&)> layerVisibilityChanged;
     std::function<void (Layer&)> layerPaintPropertyChanged;
     std::function<void (Layer&)> layerLayoutPropertyChanged;
 };

test/style/style_layer.cpp

@@ -226,6 +226,15 @@ TEST(Layer, Observer) {
     layer->setFilter(NullFilter());
     EXPECT_TRUE(filterChanged);
 
+    // Notifies observer on visibility change.
+    bool visibilityChanged = false;
+    observer.layerVisibilityChanged = [&] (Layer& layer_) {
+        EXPECT_EQ(layer.get(), &layer_);
+        visibilityChanged = true;
+    };
+    layer->setVisibility(VisibilityType::None);
+    EXPECT_TRUE(visibilityChanged);
+
     // Notifies observer on paint property change.
     bool paintPropertyChanged = false;
     observer.layerPaintPropertyChanged = [&] (Layer& layer_) {
@@ -244,6 +253,11 @@ TEST(Layer, Observer) {
     layer->setLineCap(lineCap);
     EXPECT_TRUE(layoutPropertyChanged);
 
+    // Does not notify observer on no-op visibility change.
+    visibilityChanged = false;
+    layer->setVisibility(VisibilityType::None);
+    EXPECT_FALSE(visibilityChanged);
+
     // Does not notify observer on no-op paint property change.
     paintPropertyChanged = false;
     layer->setLineColor(color);