[core] Use PropertyValue<T> for Annotation line/fill

include/mbgl/annotation/annotation.hpp

@@ -3,6 +3,7 @@
 #include <mbgl/util/geometry.hpp>
 #include <mbgl/util/variant.hpp>
 #include <mbgl/util/color.hpp>
+#include <mbgl/style/property_value.hpp>
 
 #include <cstdint>
 #include <vector>
@@ -28,17 +29,17 @@ using ShapeAnnotationGeometry = variant<
 class LineAnnotation {
 public:
     ShapeAnnotationGeometry geometry;
-    float opacity = 1;
-    float width = 1;
-    Color color = Color::black();
+    style::PropertyValue<float> opacity { 1.0f };
+    style::PropertyValue<float> width { 1.0f };
+    style::PropertyValue<Color> color { Color::black() };
 };
 
 class FillAnnotation {
 public:
     ShapeAnnotationGeometry geometry;
-    float opacity = 1;
-    Color color = Color::black();
-    Color outlineColor = { 0, 0, 0, -1 };
+    style::PropertyValue<float> opacity { 1.0f };
+    style::PropertyValue<Color> color { Color::black() };
+    style::PropertyValue<Color> outlineColor {};
 };
 
 // An annotation whose type and properties are sourced from a style layer.

src/mbgl/renderer/painter_fill.cpp

@@ -24,11 +24,8 @@ void Painter::renderFill(PaintParameters& parameters,
     Color fillColor = properties.fillColor;
     float opacity = properties.fillOpacity;
 
-    Color strokeColor = properties.fillOutlineColor;
-    bool isOutlineColorDefined = strokeColor.a >= 0;
-    if (!isOutlineColorDefined) {
-        strokeColor = fillColor;
-    }
+    const bool isOutlineColorDefined = !properties.fillOutlineColor.isUndefined();
+    Color strokeColor = isOutlineColorDefined? properties.fillOutlineColor : fillColor;
 
     auto worldSize = util::convert<GLfloat>(frame.framebufferSize);
 

src/mbgl/style/layers/fill_layer_properties.hpp

@@ -20,7 +20,7 @@ public:
     PaintProperty<bool> fillAntialias { true };
     PaintProperty<float> fillOpacity { 1 };
     PaintProperty<Color> fillColor { { 0, 0, 0, 1 } };
-    PaintProperty<Color> fillOutlineColor { { 0, 0, 0, -1 } };
+    PaintProperty<Color> fillOutlineColor { {} };
     PaintProperty<std::array<float, 2>> fillTranslate { {{ 0, 0 }} };
     PaintProperty<TranslateAnchorType> fillTranslateAnchor { TranslateAnchorType::Map };
     PaintProperty<std::string, CrossFadedPropertyEvaluator> fillPattern { "" };

src/mbgl/style/paint_property.hpp

@@ -39,8 +39,12 @@ public:
         return *this;
     }
 
+    bool isUndefined() const {
+        return values.find(ClassID::Default) == values.end();
+    }
+
     const PropertyValue<T>& get() const {
-        return values.at(ClassID::Default);
+        return isUndefined() ? values.at(ClassID::Fallback) : values.at(ClassID::Default);
     }
 
     void set(const PropertyValue<T>& value_, const optional<std::string>& klass) {

test/api/annotations.cpp

@@ -53,8 +53,8 @@ TEST(Annotations, LineAnnotation) {
 
     LineString<double> line = {{ { 0, 0 }, { 45, 45 }, { 30, 0 } }};
     LineAnnotation annotation { line };
-    annotation.color = { 255, 0, 0, 1 };
-    annotation.width = 5;
+    annotation.color = { { 255, 0, 0, 1 } };
+    annotation.width = { 5 };
 
     test.map.setStyleJSON(util::read_file("test/fixtures/api/empty.json"));
     test.map.addAnnotation(annotation);
@@ -69,7 +69,7 @@ TEST(Annotations, FillAnnotation) {
 
     Polygon<double> polygon = {{ {{ { 0, 0 }, { 0, 45 }, { 45, 45 }, { 45, 0 } }} }};
     FillAnnotation annotation { polygon };
-    annotation.color = { 255, 0, 0, 1 };
+    annotation.color = { { 255, 0, 0, 1 } };
 
     test.map.setStyleJSON(util::read_file("test/fixtures/api/empty.json"));
     test.map.addAnnotation(annotation);
@@ -110,7 +110,7 @@ TEST(Annotations, NonImmediateAdd) {
 
     Polygon<double> polygon = {{ {{ { 0, 0 }, { 0, 45 }, { 45, 45 }, { 45, 0 } }} }};
     FillAnnotation annotation { polygon };
-    annotation.color = { 255, 0, 0, 1 };
+    annotation.color = { { 255, 0, 0, 1 } };
 
     test.map.addAnnotation(annotation);
     test.checkRendering("non_immediate_add");
@@ -162,8 +162,8 @@ TEST(Annotations, RemoveShape) {
 
     LineString<double> line = {{ { 0, 0 }, { 45, 45 } }};
     LineAnnotation annotation { line };
-    annotation.color = { 255, 0, 0, 1 };
-    annotation.width = 5;
+    annotation.color = { { 255, 0, 0, 1 } };
+    annotation.width = { 5 };
 
     test.map.setStyleJSON(util::read_file("test/fixtures/api/empty.json"));
     AnnotationID shape = test.map.addAnnotation(annotation);