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.

15 files changed, 93 insertions, 15 deletions

diff --git a/include/mbgl/style/conversion/rotation.hpp b/include/mbgl/style/conversion/rotation.hpp
new file mode 100644
index 0000000000..86d67240fd
--- /dev/null
+++ b/include/mbgl/style/conversion/rotation.hpp
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <mbgl/style/conversion.hpp>
+#include <mbgl/style/rotation.hpp>
+#include <mbgl/util/optional.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+template <>
+struct Converter<style::Rotation> {
+    optional<style::Rotation> operator()(const Convertible& value, Error& error) const;
+};
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl
diff --git a/include/mbgl/style/conversion_impl.hpp b/include/mbgl/style/conversion_impl.hpp
index 79e9301842..8652a355f1 100644
--- a/include/mbgl/style/conversion_impl.hpp
+++ b/include/mbgl/style/conversion_impl.hpp
@@ -5,6 +5,7 @@
 #include <mbgl/style/expression/image.hpp>
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/property_value.hpp>
+#include <mbgl/style/rotation.hpp>
 #include <mbgl/style/transition_options.hpp>
 #include <mbgl/util/feature.hpp>
 #include <mbgl/util/geojson.hpp>
@@ -343,6 +344,11 @@ struct ValueFactory<Position> {
     }
 };
 
+template <>
+struct ValueFactory<Rotation> {
+    static Value make(const Rotation& rotation) { return {rotation.getAngle()}; }
+};
+
 template <typename T>
 Value makeValue(T&& arg) {
     return ValueFactory<std::decay_t<T>>::make(std::forward<T>(arg));
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
diff --git a/include/mbgl/style/layers/background_layer.hpp b/include/mbgl/style/layers/background_layer.hpp
index 9fdfd3ac92..2a46b2fc21 100644
--- a/include/mbgl/style/layers/background_layer.hpp
+++ b/include/mbgl/style/layers/background_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/circle_layer.hpp b/include/mbgl/style/layers/circle_layer.hpp
index dd5b674002..f0e9787caa 100644
--- a/include/mbgl/style/layers/circle_layer.hpp
+++ b/include/mbgl/style/layers/circle_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/fill_extrusion_layer.hpp b/include/mbgl/style/layers/fill_extrusion_layer.hpp
index ca33c6c3f8..3e4973b82c 100644
--- a/include/mbgl/style/layers/fill_extrusion_layer.hpp
+++ b/include/mbgl/style/layers/fill_extrusion_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/fill_layer.hpp b/include/mbgl/style/layers/fill_layer.hpp
index 4a1f09cca0..fb386c4b11 100644
--- a/include/mbgl/style/layers/fill_layer.hpp
+++ b/include/mbgl/style/layers/fill_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/heatmap_layer.hpp b/include/mbgl/style/layers/heatmap_layer.hpp
index 588aaa81df..371e9a8aa4 100644
--- a/include/mbgl/style/layers/heatmap_layer.hpp
+++ b/include/mbgl/style/layers/heatmap_layer.hpp
@@ -8,7 +8,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/hillshade_layer.hpp b/include/mbgl/style/layers/hillshade_layer.hpp
index c501e80b8d..7149fb46dd 100644
--- a/include/mbgl/style/layers/hillshade_layer.hpp
+++ b/include/mbgl/style/layers/hillshade_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/layers/layer.hpp.ejs b/include/mbgl/style/layers/layer.hpp.ejs
index a083829f60..a81aaa9e16 100644
--- a/include/mbgl/style/layers/layer.hpp.ejs
+++ b/include/mbgl/style/layers/layer.hpp.ejs
@@ -15,7 +15,12 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
+<% if (type === 'location-indicator') { -%>
+#include <mbgl/style/rotation.hpp>
+<% } -%>
+<% if (type === 'symbol') { -%>
 #include <mbgl/style/expression/formatted.hpp>
+<% } -%>
 #include <mbgl/util/color.hpp>
 
 <% if (type === 'line' || type === 'symbol') { -%>
diff --git a/include/mbgl/style/layers/line_layer.hpp b/include/mbgl/style/layers/line_layer.hpp
index 2186f16669..7d7da47bf9 100644
--- a/include/mbgl/style/layers/line_layer.hpp
+++ b/include/mbgl/style/layers/line_layer.hpp
@@ -8,7 +8,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 #include <vector>
diff --git a/include/mbgl/style/layers/location_indicator_layer.hpp b/include/mbgl/style/layers/location_indicator_layer.hpp
index e9e67c1a20..f112664dab 100644
--- a/include/mbgl/style/layers/location_indicator_layer.hpp
+++ b/include/mbgl/style/layers/location_indicator_layer.hpp
@@ -7,7 +7,7 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
+#include <mbgl/style/rotation.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
@@ -22,10 +22,6 @@ public:
 
     // Layout properties
 
-    static PropertyValue<float> getDefaultBearing();
-    const PropertyValue<float>& getBearing() const;
-    void setBearing(const PropertyValue<float>&);
-
     static PropertyValue<expression::Image> getDefaultBearingImage();
     const PropertyValue<expression::Image>& getBearingImage() const;
     void setBearingImage(const PropertyValue<expression::Image>&);
@@ -66,6 +62,12 @@ public:
     void setAccuracyRadiusColorTransition(const TransitionOptions&);
     TransitionOptions getAccuracyRadiusColorTransition() const;
 
+    static PropertyValue<Rotation> getDefaultBearing();
+    const PropertyValue<Rotation>& getBearing() const;
+    void setBearing(const PropertyValue<Rotation>&);
+    void setBearingTransition(const TransitionOptions&);
+    TransitionOptions getBearingTransition() const;
+
     static PropertyValue<float> getDefaultBearingImageSize();
     const PropertyValue<float>& getBearingImageSize() const;
     void setBearingImageSize(const PropertyValue<float>&);
diff --git a/include/mbgl/style/layers/raster_layer.hpp b/include/mbgl/style/layers/raster_layer.hpp
index df82c93660..78fa3db23b 100644
--- a/include/mbgl/style/layers/raster_layer.hpp
+++ b/include/mbgl/style/layers/raster_layer.hpp
@@ -7,7 +7,6 @@
 #include <mbgl/style/layer.hpp>
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/property_value.hpp>
-#include <mbgl/style/expression/formatted.hpp>
 #include <mbgl/util/color.hpp>
 
 namespace mbgl {
diff --git a/include/mbgl/style/rotation.hpp b/include/mbgl/style/rotation.hpp
new file mode 100644
index 0000000000..862ede93b7
--- /dev/null
+++ b/include/mbgl/style/rotation.hpp
@@ -0,0 +1,25 @@
+#pragma once
+
+namespace mbgl {
+namespace style {
+
+// Could be made a template class if needed
+// template <size_t Period>
+// size_t period() const noexcept { return Period; }
+class Rotation {
+public:
+    Rotation() = default;
+    Rotation(double angle_) : angle(angle_) {}
+    double period() const noexcept { return 360.0; }
+    double getAngle() const noexcept { return angle; }
+
+    friend bool operator==(const Rotation& lhs, const Rotation& rhs) { return lhs.angle == rhs.angle; }
+
+    friend bool operator!=(const Rotation& lhs, const Rotation& rhs) { return !(lhs == rhs); }
+
+private:
+    double angle;
+};
+
+} // namespace style
+} // namespace mbgl
diff --git a/include/mbgl/util/interpolate.hpp b/include/mbgl/util/interpolate.hpp
index aff730a0a2..566f2b0a6b 100644
--- a/include/mbgl/util/interpolate.hpp
+++ b/include/mbgl/util/interpolate.hpp
@@ -1,9 +1,10 @@
 #pragma once
 
+#include <mbgl/style/expression/value.hpp>
+#include <mbgl/style/position.hpp>
+#include <mbgl/style/rotation.hpp>
 #include <mbgl/util/color.hpp>
 #include <mbgl/util/range.hpp>
-#include <mbgl/style/position.hpp>
-#include <mbgl/style/expression/value.hpp>
 
 #include <array>
 #include <vector>
@@ -102,6 +103,27 @@ public:
     }
 };
 
+template <>
+struct Interpolator<style::Rotation> {
+public:
+    style::Rotation operator()(const style::Rotation& a, const style::Rotation& b, const double t) {
+        assert(a.period() == b.period());
+        auto period = a.period();
+        auto aAngle = std::fmod(a.getAngle(), period);
+        auto bAngle = std::fmod(b.getAngle(), period);
+
+        if (aAngle - bAngle > period * 0.5) {
+            return {std::fmod(aAngle * (1.0 - t) + (bAngle + period) * t, period)};
+        }
+
+        if (aAngle - bAngle < period * -0.5) {
+            return {std::fmod((aAngle + period) * (1.0 - t) + bAngle * t, period)};
+        }
+
+        return {aAngle * (1.0 - t) + bAngle * t};
+    }
+};
+
 struct Uninterpolated {
     template <class T>
     T operator()(const T& a, const T&, const double) const {