1 files changed, 41 insertions, 0 deletions
diff --git a/include/mbgl/style/function/camera_function.hpp b/include/mbgl/style/function/camera_function.hpp
new file mode 100644
index 0000000000..a96978939d
--- /dev/null
+++ b/include/mbgl/style/function/camera_function.hpp
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <mbgl/style/function/exponential_stops.hpp>
+#include <mbgl/style/function/interval_stops.hpp>
+#include <mbgl/util/interpolate.hpp>
+#include <mbgl/util/variant.hpp>
+
+namespace mbgl {
+namespace style {
+
+template <class T>
+class CameraFunction {
+public:
+    using Stops = std::conditional_t<
+        util::Interpolatable<T>,
+        variant<
+            ExponentialStops<T>,
+            IntervalStops<T>>,
+        variant<
+            IntervalStops<T>>>;
+
+    CameraFunction(Stops stops_)
+        : stops(std::move(stops_)) {
+    }
+
+    T evaluate(float zoom) const {
+        return stops.match([&] (const auto& s) {
+            return s.evaluate(Value(double(zoom)));
+        });
+    }
+
+    friend bool operator==(const CameraFunction& lhs,
+                           const CameraFunction& rhs) {
+        return lhs.stops == rhs.stops;
+    }
+
+    Stops stops;
+};
+
+} // namespace style
+} // namespace mbgl