Make location indicator bearing a paint property

This change introduces a new property type, Rotation, that uses
a custom interpolator, and that is currently applied to
all style properties named "bearing", with a period attribute.

1 files changed, 8 insertions, 0 deletions

diff --git a/include/mbgl/style/expression/value.hpp b/include/mbgl/style/expression/value.hpp
index 902f5ae209..6f12bb9336 100644
--- a/include/mbgl/style/expression/value.hpp
+++ b/include/mbgl/style/expression/value.hpp
@@ -5,6 +5,7 @@
 #include <mbgl/style/expression/image.hpp>
 #include <mbgl/style/expression/type.hpp>
 #include <mbgl/style/position.hpp>
+#include <mbgl/style/rotation.hpp>
 #include <mbgl/style/types.hpp>
 #include <mbgl/util/color.hpp>
 #include <mbgl/util/enum.hpp>
@@ -147,6 +148,13 @@ std::vector<optional<T>> fromExpressionValues(const std::vector<optional<Value>>
     return result;
 }
 
+template <>
+struct ValueConverter<Rotation> {
+    static type::Type expressionType() { return type::Number; }
+    static Value toExpressionValue(const mbgl::style::Rotation& value);
+    static optional<Rotation> fromExpressionValue(const Value& v);
+};
+
 } // namespace expression
 } // namespace style
 } // namespace mbgl