Implement Style::isLoaded

src/mbgl/map/map_context.cpp

@@ -236,7 +236,7 @@ void MapContext::render() {
 
     painter->render(*style, data.getTransformState(), data.getAnimationTime());
 
-    if (data.mode == MapMode::Still && data.callback /* && loaded() */) {
+    if (data.mode == MapMode::Still && data.callback && style->isLoaded() && getSprite()->isLoaded()) {
         auto image = view.readStillImage();
 
         // We are moving the callback out of the way and empty it in case the callback function

src/mbgl/map/source.cpp

@@ -118,6 +118,20 @@ Source::Source()
 
 Source::~Source() {}
 
+bool Source::isLoaded() const {
+    if (!loaded) {
+        return false;
+    }
+
+    for (const auto& tile : tiles) {
+        if (tile.second->data->state != TileData::State::parsed) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 // Note: This is a separate function that must be called exactly once after creation
 // The reason this isn't part of the constructor is that calling shared_from_this() in
 // the constructor fails.

src/mbgl/map/source.hpp

@@ -60,6 +60,7 @@ public:
     void load(const std::string& accessToken,
               Environment&,
               std::function<void()> callback);
+    bool isLoaded() const;
 
     void load(MapData&, Environment&, std::function<void()> callback);
     void update(MapData&,

src/mbgl/style/style.cpp

@@ -86,4 +86,24 @@ void Style::loadJSON(const uint8_t *const data) {
     glyph_url = parser.getGlyphURL();
 }
 
+bool Style::isLoaded() const {
+    // TODO: move loading into Style
+//    if (!loaded) {
+//        return false;
+//    }
+
+    for (const auto& source : sources) {
+        if (!source->isLoaded()) {
+            return false;
+        }
+    }
+
+    // TODO: move sprite into Style
+//    if (sprite && !sprite.isLoaded()) {
+//        return false;
+//    }
+
+    return true;
+}
+
 }

src/mbgl/style/style.hpp

@@ -24,6 +24,7 @@ public:
     ~Style();
 
     void loadJSON(const uint8_t *const data);
+    bool isLoaded() const;
 
     void cascade(const std::vector<std::string>&);
     void recalculate(float z, TimePoint now);