1 files changed, 94 insertions, 0 deletions
diff --git a/include/mbgl/style/style_layer.hpp b/include/mbgl/style/style_layer.hpp
new file mode 100644
index 0000000000..14d60ed9b6
--- /dev/null
+++ b/include/mbgl/style/style_layer.hpp
@@ -0,0 +1,94 @@
+#ifndef MBGL_STYLE_STYLE_LAYER
+#define MBGL_STYLE_STYLE_LAYER
+
+#include <mbgl/style/class_dictionary.hpp>
+#include <mbgl/style/class_properties.hpp>
+#include <mbgl/style/style_properties.hpp>
+#include <mbgl/style/rasterize_properties.hpp>
+#include <mbgl/style/applied_class_properties.hpp>
+
+#include <vector>
+#include <memory>
+#include <string>
+#include <map>
+#include <set>
+
+namespace mbgl {
+
+class StyleBucket;
+class StyleLayerGroup;
+
+class StyleLayer {
+public:
+    StyleLayer(const std::string &id, std::map<ClassID, ClassProperties> &&styles,
+        std::unique_ptr<const RasterizeProperties> &&rasterize);
+
+    template <typename T> const T &getProperties() {
+        if (properties.is<T>()) {
+            return properties.get<T>();
+        } else {
+            return defaultStyleProperties<T>();
+        }
+    }
+
+    // Determines whether this layer is the background layer.
+    bool isBackground() const;
+
+    // Updates the StyleProperties information in this layer by evaluating all
+    // pending transitions and applied classes in order.
+    void updateProperties(float z, timestamp now);
+
+    // Sets the list of classes and creates transitions to the currently applied values.
+    void setClasses(const std::vector<std::string> &class_names, timestamp now,
+                    const PropertyTransition &defaultTransition);
+
+    bool hasTransitions() const;
+
+private:
+    // Applies all properties from a class, if they haven't been applied already.
+    void applyClassProperties(ClassID class_id, std::set<PropertyKey> &already_applied,
+                              timestamp now, const PropertyTransition &defaultTransition);
+
+    // Sets the properties of this object by evaluating all pending transitions and
+    // aplied classes in order.
+    template <typename T> void applyStyleProperties(float z, timestamp now);
+    template <typename T> void applyStyleProperty(PropertyKey key, T &, float z, timestamp now);
+
+    // Removes all expired style transitions.
+    void cleanupAppliedStyleProperties(timestamp now);
+
+public:
+    // The name of this layer.
+    const std::string id;
+
+    StyleLayerType type = StyleLayerType::Unknown;
+
+    // Bucket information, telling the renderer how to generate the geometries
+    // for this layer (feature property filters, tessellation instructions, ...).
+    std::shared_ptr<StyleBucket> bucket;
+
+    // Contains all style classes that can be applied to this layer.
+    const std::map<ClassID, ClassProperties> styles;
+
+private:
+    // For every property, stores a list of applied property values, with
+    // optional transition times.
+    std::map<PropertyKey, AppliedClassProperties> appliedStyle;
+
+public:
+    // Stores the evaluated, and cascaded styling information, specific to this
+    // layer's type.
+    StyleProperties properties;
+
+    // Rasterization properties are used for prerendering the tile to a bitmap,
+    // which is then used as a raster image instead of rendering this layer
+    // directly in every frame.
+    const std::unique_ptr<const RasterizeProperties> rasterize;
+
+    // Child layer array (if this layer has child layers).
+    std::shared_ptr<StyleLayerGroup> layers;
+};
+
+}
+
+#endif