Add enabled flag to Item

- Adds the enabled flag as well as get and set methods.
- Adds Python bindings.
- Add .otio read and write code.

Author: ThomasWilshaw

src/opentimelineio/item.cpp

@@ -17,6 +17,7 @@ Item::Item(
     , _source_range(source_range)
     , _effects(effects.begin(), effects.end())
     , _markers(markers.begin(), markers.end())
+    , _enabled(true)
 {}
 
 Item::~Item()
@@ -165,6 +166,7 @@ Item::read_from(Reader& reader)
     return reader.read_if_present("source_range", &_source_range) &&
            reader.read_if_present("effects", &_effects) &&
            reader.read_if_present("markers", &_markers) &&
+           reader.read_if_present("enabled", &_enabled) &&
            Parent::read_from(reader);
 }
 
@@ -175,6 +177,7 @@ Item::write_to(Writer& writer) const
     writer.write("source_range", _source_range);
     writer.write("effects", _effects);
     writer.write("markers", _markers);
+    writer.write("enabled", _enabled);
 }
 
 }} // namespace opentimelineio::OPENTIMELINEIO_VERSION

src/opentimelineio/item.h

@@ -31,6 +31,13 @@ class Item : public Composable
 
     virtual bool visible() const;
     virtual bool overlapping() const;
+    
+    bool enabled() const { return _enabled; };
+
+    void set_enabled(bool enabled)
+    {
+        _enabled = enabled;
+    }
 
     optional<TimeRange> source_range() const noexcept { return _source_range; }
 
@@ -90,6 +97,7 @@ class Item : public Composable
     optional<TimeRange>           _source_range;
     std::vector<Retainer<Effect>> _effects;
     std::vector<Retainer<Marker>> _markers;
+    bool                          _enabled;
 };
 
 }} // namespace opentimelineio::OPENTIMELINEIO_VERSION

src/py-opentimelineio/opentimelineio-bindings/otio_serializableObjects.cpp

@@ -305,6 +305,7 @@ static void define_items_and_compositions(py::module m) {
              "effects"_a = py::none(),
              "markers"_a = py::none(),
              py::arg_v("metadata"_a = py::none()))
+        .def_property("enabled", &Item::enabled, &Item::set_enabled)
         .def_property("source_range", &Item::source_range, &Item::set_source_range)
         .def("available_range", [](Item* item) {
             return item->available_range(ErrorStatusHandler());