GPv3: Duplicate operator (edit mode)

Code by @filedescriptor

@@ -714,7 +715,6 @@ static void GREASE_PENCIL_OT_delete(wmOperatorType *ot)
   ot->description = "Delete selected strokes or points";
 
   /* Callbacks. */
-  ot->invoke = WM_menu_invoke;

@@ -664,6 +664,7 @@ static bke::CurvesGeometry remove_points_and_split(const bke::CurvesGeometry &cu
   /* Transfer point attributes. */
   gather_attributes(src_attributes, ATTR_DOMAIN_POINT, {}, {}, dst_to_src_point, dst_attributes);
 
+  dst_curves.update_curve_types();

@@ -1451,0 +1460,4 @@
+
+  Array<bool> points_to_duplicate(curves.points_num());
+  mask.to_bools(points_to_duplicate.as_mutable_span());
+  const int num_points_to_add = points_to_duplicate.as_span().count(true);

@@ -1451,0 +1463,4 @@
+  const int num_points_to_add = points_to_duplicate.as_span().count(true);
+
+  int curr_dst_point_id = 0;
+  Array<int> dst_to_src_point(curves.points_num() + num_points_to_add);

@@ -1451,0 +1484,4 @@
+  }
+
+  /* Add the duplicated curves and points. */
+  for (const int curve_i : curves.curves_range()) {

@@ -1451,0 +1503,4 @@
+    const bool is_curve_self_joined = is_last_segment_selected && ranges_to_duplicate.size() != 1;
+    const bool is_cyclic = ranges_to_duplicate.size() == 1 && is_last_segment_selected;
+
+    IndexRange range_ids = ranges_to_duplicate.index_range();

@@ -1451,0 +1564,4 @@
+  Object *object = CTX_data_active_object(C);
+  GreasePencil &grease_pencil = *static_cast<GreasePencil *>(object->data);
+
+  bool changed = false;

@@ -1451,0 +1577,4 @@
+    bke::CurvesGeometry &curves = info.drawing.strokes_for_write();
+    curves = duplicate_points(curves, points);
+    info.drawing.tag_topology_changed();
+    changed = true;

@@ -1451,0 +1505,4 @@
+      const IndexRange range = ranges_to_duplicate[range_i];
+
+      int count = range.size();
+      for (const int src_point : range.shift(points.first())) {

@@ -1451,0 +1511,4 @@
+
+      /* Join the first range to the end of the last range. */
+      if (is_curve_self_joined && range_i == range_ids.last()) {
+        const IndexRange first_range = ranges_to_duplicate[range_ids.first()];

@@ -1451,0 +1512,4 @@
+      /* Join the first range to the end of the last range. */
+      if (is_curve_self_joined && range_i == range_ids.last()) {
+        const IndexRange first_range = ranges_to_duplicate[range_ids.first()];
+        for (const int src_point : first_range.shift(points.first())) {

@@ -1451,0 +1581,4 @@
+    WM_event_add_notifier(C, NC_GEOM | ND_DATA, &grease_pencil);
+  }
+  return OPERATOR_FINISHED;
+}

@@ -1451,0 +1464,4 @@
+
+  /* Add all of the orignal curves and points. */
+  Array<int> dst_to_src_point(curves.points_num() + num_points_to_add);
+  array_utils::fill_index_range<int>(

@@ -1451,0 +1537,4 @@
+    if (meta_data.domain == ATTR_DOMAIN_CURVE && id.name() == "cyclic") {
+      return true;
+    }
+    const bke::GAttributeReader src = src_attributes.lookup(id, meta_data.domain);

@@ -1451,0 +1544,4 @@
+      return true;
+    }
+
+    if (meta_data.domain == ATTR_DOMAIN_CURVE) {

@@ -1451,0 +1561,4 @@
+  array_utils::copy(dst_cyclic.as_span(), curves.cyclic_for_write().drop_front(old_curves_num));
+
+  /* Deselect the original curves. */
+  bke::GSpanAttributeWriter selection = ed::curves::ensure_selection_attribute(

@@ -1451,0 +1602,4 @@
+  /* Identifiers. */
+  ot->name = "Duplicate";
+  ot->idname = "GREASE_PENCIL_OT_duplicate";
+  ot->description = "Duplicate the selected strokes";

@@ -1451,0 +1539,4 @@
+        if (id.name() == "cyclic") {
+          return true;
+        }
+

@@ -1451,0 +1560,4 @@
+        BLI_assert_unreachable();
+        return true;
+        break;
+      };

@@ -1451,0 +1568,4 @@
+    return true;
+  });
+  array_utils::copy(dst_cyclic.as_span(), curves.cyclic_for_write().drop_front(old_curves_num));
+

@@ -1451,0 +1533,4 @@
+    if (!attribute) {
+      return true;
+    }
+    if (id.name() == ".selection") {