[core] Split Interpolator into a separate file

2 files changed, 51 insertions, 42 deletions

diff --git a/include/mbgl/style/expression/interpolate.hpp b/include/mbgl/style/expression/interpolate.hpp
index cc744ac7b7..1f73fc14b4 100644
--- a/include/mbgl/style/expression/interpolate.hpp
+++ b/include/mbgl/style/expression/interpolate.hpp
@@ -3,12 +3,9 @@
 #include <mbgl/style/expression/expression.hpp>
 #include <mbgl/style/expression/parsing_context.hpp>
 #include <mbgl/style/expression/get_covering_stops.hpp>
+#include <mbgl/style/expression/interpolator.hpp>
 #include <mbgl/style/conversion.hpp>
 
-#include <mbgl/util/interpolate.hpp>
-#include <mbgl/util/range.hpp>
-#include <mbgl/util/unitbezier.hpp>
-
 #include <memory>
 #include <map>
 #include <cmath>
@@ -17,48 +14,10 @@ namespace mbgl {
 namespace style {
 namespace expression {
 
-class ExponentialInterpolator {
-public:
-    ExponentialInterpolator(double base_) : base(base_) {}
-
-    double base;
-    
-    double interpolationFactor(const Range<double>& inputLevels, const double input) const {
-        return util::interpolationFactor(base,
-                                         Range<float> {
-                                            static_cast<float>(inputLevels.min),
-                                            static_cast<float>(inputLevels.max)
-                                         },
-                                         input);
-    }
-    
-    bool operator==(const ExponentialInterpolator& rhs) const {
-        return base == rhs.base;
-    }
-};
-
-class CubicBezierInterpolator {
-public:
-    CubicBezierInterpolator(double x1_, double y1_, double x2_, double y2_) : ub(x1_, y1_, x2_, y2_) {}
-    
-    double interpolationFactor(const Range<double>& inputLevels, const double input) const {
-        return ub.solve(input / (inputLevels.max - inputLevels.min), 1e-6);
-    }
-    
-    bool operator==(const CubicBezierInterpolator& rhs) const {
-        return ub == rhs.ub;
-    }
-    
-    util::UnitBezier ub;
-};
-
-
 ParseResult parseInterpolate(const mbgl::style::conversion::Convertible& value, ParsingContext& ctx);
 
 class InterpolateBase : public Expression {
 public:
-    using Interpolator = variant<ExponentialInterpolator, CubicBezierInterpolator>;
-
     InterpolateBase(const type::Type& type_,
           Interpolator interpolator_,
           std::unique_ptr<Expression> input_,
diff --git a/include/mbgl/style/expression/interpolator.hpp b/include/mbgl/style/expression/interpolator.hpp
new file mode 100644
index 0000000000..f37fb2c9cd
--- /dev/null
+++ b/include/mbgl/style/expression/interpolator.hpp
@@ -0,0 +1,50 @@
+#pragma once
+
+#include <mbgl/util/interpolate.hpp>
+#include <mbgl/util/range.hpp>
+#include <mbgl/util/unitbezier.hpp>
+
+namespace mbgl {
+namespace style {
+namespace expression {
+
+class ExponentialInterpolator {
+public:
+    ExponentialInterpolator(double base_) : base(base_) {}
+
+    double base;
+    
+    double interpolationFactor(const Range<double>& inputLevels, const double input) const {
+        return util::interpolationFactor(base,
+                                         Range<float> {
+                                            static_cast<float>(inputLevels.min),
+                                            static_cast<float>(inputLevels.max)
+                                         },
+                                         input);
+    }
+    
+    bool operator==(const ExponentialInterpolator& rhs) const {
+        return base == rhs.base;
+    }
+};
+
+class CubicBezierInterpolator {
+public:
+    CubicBezierInterpolator(double x1_, double y1_, double x2_, double y2_) : ub(x1_, y1_, x2_, y2_) {}
+    
+    double interpolationFactor(const Range<double>& inputLevels, const double input) const {
+        return ub.solve(input / (inputLevels.max - inputLevels.min), 1e-6);
+    }
+    
+    bool operator==(const CubicBezierInterpolator& rhs) const {
+        return ub == rhs.ub;
+    }
+    
+    util::UnitBezier ub;
+};
+
+using Interpolator = variant<ExponentialInterpolator, CubicBezierInterpolator>;
+
+} // namespace expression
+} // namespace style
+} // namespace mbgl