Curves: Transform Bezier handles

In the scope of `TransConvertType_Curve.create_trans_data` call method `handle_positions_left_for_write` is called and it's return value is left referenced by `TransInfo.data_container.data.loc`s. Latter after few frames in the scope of `TransConvertType_Curve.recalcData_curve` call method `handle_positions_left_for_write` gets called again, but layer's `sharing_info` has 2 strong users and layer gets copied and latter deleted (probably then second strong user also gets deleted) though layer's data is still referenced by `TransInfo`. To avoid this same reference to layer's data is shared between `TransConvertType_Curve.create_trans_data` and `TransConvertType_Curve.recalcData_curve` during all transformation process.

@@ -82,3 +133,2 @@
     else {
-      selection_per_object[i] = ed::curves::retrieve_selected_points(curves, memory);
-      tc.data_len = selection_per_object[i].size();
+      tc.data_len = std::reduce(

@@ -67,0 +72,4 @@
+  int offset = 0;
+  for (const int i : src_offsets.index_range()) {
+    dst_offsets[i] = offset;
+    offset += src_offsets[i].size() * (selection.contains(i) ? multiplier : 1);

@@ -96,0 +116,4 @@
+                                                     curves.curves_range(),
+                                                     curves_transform_data->memory);
+    /* Alter selection as in legacy curves bezt_select_to_transform_triple_flag(). */
+    if (bezier_curves[i].size()) {

@@ -96,0 +138,4 @@
+      IndexMask must_be_selected_mask = IndexMask::from_indices(must_be_selected.as_span(),
+                                                                curves_transform_data->memory);
+      if (must_be_selected.size()) {
+        selection_per_attribute[i][1] = IndexMask::from_union(

@@ -96,0 +145,4 @@
+      }
+    }
+
+    int positions_in_custom_data = 0;

@@ -169,0 +233,4 @@
+          curves.positions_for_write(),
+          curves.handle_positions_left_for_write(),
+          curves.handle_positions_right_for_write()};
+      for (const int layer :

@@ -215,2 +288,4 @@
+                                       const blender::IndexMask &bezier_curves)
 {
   using namespace blender;
+  /* Term layer in function is used to refer Bezier curve points, left and right handles as layers

@@ -149,6 +149,11 @@ void gather_group_sizes(OffsetIndices<int> offsets, const IndexMask &mask, Mutab
 
 void gather_group_sizes(OffsetIndices<int> offsets, Span<int> indices, MutableSpan<int> sizes);
 
+OffsetIndices<int> expand_selected_offsets(const OffsetIndices<int> src_offsets,

@@ -173,6 +248,33 @@ static void recalcData_curves(TransInfo *t)
   }
 }
 
+static OffsetIndices<int> expand_selected_offsets(const OffsetIndices<int> src_offsets,

@@ -95,0 +127,4 @@
+            if (ELEM(type_left, BEZIER_HANDLE_AUTO, BEZIER_HANDLE_ALIGN) &&
+                ELEM(type_right, BEZIER_HANDLE_AUTO, BEZIER_HANDLE_ALIGN))
+            {
+              must_be_selected.append(point_i);

@@ -176,0 +259,4 @@
+}
+
+/**
+ * Creates map of indexes to `tc.data` representing curve in layout

@@ -176,0 +265,4 @@
+ */
+static void fill_map(const CurveType curve_type,
+                     MutableSpan<int> map,
+                     IndexRange curve_points,

@@ -240,0 +410,4 @@
+        const int selection_attrs_num = curve_types[curve_i] == CURVE_TYPE_BEZIER ? 3 : 1;
+        const IndexRange curve_points = points_by_curve[curve_i];
+        const int total_curve_points = selection_attrs_num * curve_points.size();
+        map.reinitialize(total_curve_points);

@@ -117,3 +116,2 @@
                                         value_attribute,
-                                        points,
-                                        use_proportional_edit,
+                                        Span(&points, 1),