Parse and expose more style JSON root properties

include/mbgl/map/map.hpp

@@ -158,6 +158,13 @@ class Map : private util::noncopyable {
     void addLayer(std::unique_ptr<style::Layer>, const optional<std::string>& beforeLayerID = {});
     void removeLayer(const std::string& layerID);
 
+    // Defaults
+    std::string getStyleName() const;
+    LatLng getDefaultLatLng() const;
+    double getDefaultZoom() const;
+    double getDefaultBearing() const;
+    double getDefaultPitch() const;
+
     // Feature queries
     std::vector<Feature> queryRenderedFeatures(const ScreenCoordinate&, const optional<std::vector<std::string>>& layerIDs = {});
     std::vector<Feature> queryRenderedFeatures(const ScreenBox&,        const optional<std::vector<std::string>>& layerIDs = {});

src/mbgl/map/map.cpp

@@ -781,6 +781,28 @@ void Map::removeLayer(const std::string& id) {
     impl->view.deactivate();
 }
 
+#pragma mark - Defaults
+
+std::string Map::getStyleName() const {
+    return impl->style->getName();
+}
+
+LatLng Map::getDefaultLatLng() const {
+    return impl->style->getDefaultLatLng();
+}
+
+double Map::getDefaultZoom() const {
+    return impl->style->getDefaultZoom();
+}
+
+double Map::getDefaultBearing() const {
+    return impl->style->getDefaultBearing();
+}
+
+double Map::getDefaultPitch() const {
+    return impl->style->getDefaultPitch();
+}
+
 #pragma mark - Toggles
 
 void Map::setDebug(MapDebugOptions debugOptions) {

src/mbgl/style/parser.cpp

@@ -42,6 +42,43 @@ void Parser::parse(const std::string& json) {
         }
     }
 
+    if (document.HasMember("name")) {
+        const JSValue& value = document["name"];
+        if (value.IsString()) {
+            name = { value.GetString(), value.GetStringLength() };
+        }
+    }
+
+    if (document.HasMember("center")) {
+        const JSValue& value = document["center"];
+        if (value.IsArray() && value.Size() >= 2) {
+            // Style spec uses lon/lat order
+            latLng.longitude = value[0].IsNumber() ? value[0].GetDouble() : 0;
+            latLng.latitude = value[1].IsNumber() ? value[1].GetDouble() : 0;
+        }
+    }
+
+    if (document.HasMember("zoom")) {
+        const JSValue& value = document["zoom"];
+        if (value.IsNumber()) {
+            zoom = value.GetDouble();
+        }
+    }
+
+    if (document.HasMember("bearing")) {
+        const JSValue& value = document["bearing"];
+        if (value.IsNumber()) {
+            bearing = value.GetDouble();
+        }
+    }
+
+    if (document.HasMember("pitch")) {
+        const JSValue& value = document["pitch"];
+        if (value.IsNumber()) {
+            pitch = value.GetDouble();
+        }
+    }
+
     if (document.HasMember("sources")) {
         parseSources(document["sources"]);
     }

src/mbgl/style/parser.hpp

@@ -5,6 +5,7 @@
 
 #include <mbgl/util/rapidjson.hpp>
 #include <mbgl/util/font_stack.hpp>
+#include <mbgl/util/geo.hpp>
 
 #include <vector>
 #include <memory>
@@ -27,6 +28,12 @@ class Parser {
     std::vector<std::unique_ptr<Source>> sources;
     std::vector<std::unique_ptr<Layer>> layers;
 
+    std::string name;
+    LatLng latLng;
+    double zoom = 0;
+    double bearing = 0;
+    double pitch = 0;
+
     // Statically evaluate layer properties to determine what font stacks are used.
     std::vector<FontStack> fontStacks() const;
 

src/mbgl/style/style.cpp

@@ -100,6 +100,12 @@ void Style::setJSON(const std::string& json) {
         addLayer(std::move(layer));
     }
 
+    name = parser.name;
+    defaultLatLng = parser.latLng;
+    defaultZoom = parser.zoom;
+    defaultBearing = parser.bearing;
+    defaultPitch = parser.pitch;
+
     glyphStore->setURL(parser.glyphURL);
     spriteStore->load(parser.spriteURL, fileSource);
 
@@ -163,6 +169,26 @@ void Style::removeLayer(const std::string& id) {
     layers.erase(it);
 }
 
+std::string Style::getName() const {
+    return name;
+}
+
+LatLng Style::getDefaultLatLng() const {
+    return defaultLatLng;
+}
+
+double Style::getDefaultZoom() const {
+    return defaultZoom;
+}
+
+double Style::getDefaultBearing() const {
+    return defaultBearing;
+}
+
+double Style::getDefaultPitch() const {
+    return defaultPitch;
+}
+
 void Style::update(const UpdateParameters& parameters) {
     bool allTilesUpdated = true;
 

src/mbgl/style/style.hpp

@@ -13,6 +13,7 @@
 #include <mbgl/util/worker.hpp>
 #include <mbgl/util/optional.hpp>
 #include <mbgl/util/feature.hpp>
+#include <mbgl/util/geo.hpp>
 
 #include <cstdint>
 #include <string>
@@ -68,6 +69,12 @@ class Style : public GlyphStoreObserver,
                   optional<std::string> beforeLayerID = {});
     void removeLayer(const std::string& layerID);
 
+    std::string getName() const;
+    LatLng getDefaultLatLng() const;
+    double getDefaultZoom() const;
+    double getDefaultBearing() const;
+    double getDefaultPitch() const;
+
     bool addClass(const std::string&, const TransitionOptions& = {});
     bool removeClass(const std::string&, const TransitionOptions& = {});
     bool hasClass(const std::string&) const;
@@ -98,6 +105,13 @@ class Style : public GlyphStoreObserver,
     std::vector<std::string> classes;
     optional<TransitionOptions> transitionProperties;
 
+    // Defaults
+    std::string name;
+    LatLng defaultLatLng;
+    double defaultZoom;
+    double defaultBearing;
+    double defaultPitch;
+
     std::vector<std::unique_ptr<Layer>>::const_iterator findLayer(const std::string& layerID) const;
 
     // GlyphStoreObserver implementation.

test/style/style.cpp

@@ -61,3 +61,37 @@ TEST(Style, UnusedSourceActiveViaClassUpdate) {
     EXPECT_TRUE(unusedSource);
     EXPECT_FALSE(unusedSource->baseImpl->isLoaded());
 }
+
+TEST(Style, Properties) {
+    util::RunLoop loop;
+
+    StubFileSource fileSource;
+    Style style { fileSource, 1.0 };
+
+    style.setJSON(R"STYLE({"name": "Test"})STYLE");
+    ASSERT_EQ("Test", style.getName());
+
+    style.setJSON(R"STYLE({"center": [10, 20]})STYLE");
+    ASSERT_EQ("", style.getName());
+    ASSERT_EQ((LatLng{20, 10}), style.getDefaultLatLng());
+
+    style.setJSON(R"STYLE({"bearing": 24})STYLE");
+    ASSERT_EQ("", style.getName());
+    ASSERT_EQ((LatLng{0, 0}), style.getDefaultLatLng());
+    ASSERT_EQ(24, style.getDefaultBearing());
+
+    style.setJSON(R"STYLE({"zoom": 13.3})STYLE");
+    ASSERT_EQ("", style.getName());
+    ASSERT_EQ(13.3, style.getDefaultZoom());
+
+    style.setJSON(R"STYLE({"pitch": 60})STYLE");
+    ASSERT_EQ("", style.getName());
+    ASSERT_EQ(60, style.getDefaultPitch());
+
+    style.setJSON(R"STYLE({"name": 23, "center": {}, "bearing": "north", "zoom": null, "pitch": "wide"})STYLE");
+    ASSERT_EQ("", style.getName());
+    ASSERT_EQ((LatLng{0, 0}), style.getDefaultLatLng());
+    ASSERT_EQ(0, style.getDefaultBearing());
+    ASSERT_EQ(0, style.getDefaultZoom());
+    ASSERT_EQ(0, style.getDefaultPitch());
+}