Add the rendering primitives for rendering a path

Right now the path is limited to polygons (only LineTo elements) and only the fill color can be specified.

api/sixtyfps-cpp/include/sixtyfps.h

@@ -18,6 +18,7 @@ extern const internal::ItemVTable RectangleVTable;
 extern const internal::ItemVTable TextVTable;
 extern const internal::ItemVTable TouchAreaVTable;
 extern const internal::ItemVTable ImageVTable;
+extern const internal::ItemVTable PathVTable;
 }
 
 // Bring opaque structure in scope
@@ -47,6 +48,7 @@ private:
 
 using internal::EvaluationContext;
 using internal::Image;
+using internal::Path;
 using internal::Rectangle;
 using internal::Text;
 using internal::TouchArea;

api/sixtyfps-cpp/include/sixtyfps_pathelements.h

@@ -0,0 +1,34 @@
+#pragma once
+#include <initializer_list>
+#include <string_view>
+#include "sixtyfps_pathelements_internal.h"
+
+namespace sixtyfps {
+
+using internal::types::PathElement;
+
+struct PathElements
+{
+public:
+    using Tag = internal::types::PathElements::Tag;
+
+    PathElements() : data(Data::None()) { }
+    PathElements(const PathElement *firstElement, size_t count)
+        : data(Data::SharedElements(elements_from_array(firstElement, count)))
+    {
+    }
+
+private:
+    static SharedArray<PathElement> elements_from_array(const PathElement *firstElement,
+                                                        size_t count)
+    {
+        SharedArray<PathElement> tmp;
+        sixtyfps_new_path_elements(&tmp, firstElement, count);
+        return tmp;
+    }
+
+    using Data = internal::types::PathElements;
+    Data data;
+};
+
+}