D14823: Adds operator to duplicate the active color attribute layer

Fixes T97706

Adds operator to duplicate the active color attribute layer.
Adds `"Color Attribute Specials"` menu to color attribute ui to access the `"geometry.color_attribute_duplicate"` operator.
Internally adds a function that duplicates a referenced CustomDataLayer
- `BKE_id_attribute_duplicate` mostly copies the existing `BKE_id_attribute_new`
- but gets the type and domain from the referenced layer
- and copies the data from the old layer into the new layer

Reviewed By: Joseph Eagar & Hans Goudey & Julien Kaspar
Differential Revision: https://developer.blender.org/D14823
Ref D14823

3 files changed, 54 insertions, 0 deletions

diff --git a/source/blender/editors/geometry/geometry_attributes.cc b/source/blender/editors/geometry/geometry_attributes.cc
index 63059a49a9e..37ec7a61bcb 100644
--- a/source/blender/editors/geometry/geometry_attributes.cc
+++ b/source/blender/editors/geometry/geometry_attributes.cc
@@ -498,6 +498,7 @@ static bool geometry_color_attributes_remove_poll(bContext *C)
 
   return false;
 }
+
 void GEOMETRY_OT_color_attribute_remove(wmOperatorType *ot)
 {
   /* identifiers */
@@ -513,6 +514,57 @@ void GEOMETRY_OT_color_attribute_remove(wmOperatorType *ot)
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+static int geometry_color_attribute_duplicate_exec(bContext *C, wmOperator *op)
+{
+  Object *ob = ED_object_context(C);
+  ID *id = static_cast<ID *>(ob->data);
+  CustomDataLayer *layer = BKE_id_attributes_active_color_get(id);
+
+  if (layer == nullptr) {
+    return OPERATOR_CANCELLED;
+  }
+
+  CustomDataLayer *newLayer = BKE_id_attribute_duplicate(id, layer, op->reports);
+
+  BKE_id_attributes_active_color_set(id, newLayer);
+
+  DEG_id_tag_update(id, ID_RECALC_GEOMETRY);
+  WM_main_add_notifier(NC_GEOM | ND_DATA, id);
+
+  return OPERATOR_FINISHED;
+}
+
+static bool geometry_color_attributes_duplicate_poll(bContext *C)
+{
+  if (!geometry_attributes_poll(C)) {
+    return false;
+  }
+
+  Object *ob = ED_object_context(C);
+  ID *data = ob ? static_cast<ID *>(ob->data) : nullptr;
+
+  if (BKE_id_attributes_active_color_get(data) != nullptr) {
+    return true;
+  }
+
+  return false;
+}
+
+void GEOMETRY_OT_color_attribute_duplicate(wmOperatorType *ot)
+{
+  /* identifiers */
+  ot->name = "Duplicate Color Attribute";
+  ot->description = "Duplicate color attribute";
+  ot->idname = "GEOMETRY_OT_color_attribute_duplicate";
+
+  /* api callbacks */
+  ot->exec = geometry_color_attribute_duplicate_exec;
+  ot->poll = geometry_color_attributes_duplicate_poll;
+
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
 static void geometry_attribute_convert_ui(bContext *UNUSED(C), wmOperator *op)
 {
   uiLayout *layout = op->layout;
diff --git a/source/blender/editors/geometry/geometry_intern.hh b/source/blender/editors/geometry/geometry_intern.hh
index bbcb682d6bf..a1000a5d01f 100644
--- a/source/blender/editors/geometry/geometry_intern.hh
+++ b/source/blender/editors/geometry/geometry_intern.hh
@@ -17,6 +17,7 @@ void GEOMETRY_OT_attribute_remove(struct wmOperatorType *ot);
 void GEOMETRY_OT_color_attribute_add(struct wmOperatorType *ot);
 void GEOMETRY_OT_color_attribute_remove(struct wmOperatorType *ot);
 void GEOMETRY_OT_color_attribute_render_set(struct wmOperatorType *ot);
+void GEOMETRY_OT_color_attribute_duplicate(struct wmOperatorType *ot);
 void GEOMETRY_OT_attribute_convert(struct wmOperatorType *ot);
 
 }  // namespace blender::ed::geometry
diff --git a/source/blender/editors/geometry/geometry_ops.cc b/source/blender/editors/geometry/geometry_ops.cc
index 23f6e6f29f4..acac757ecf1 100644
--- a/source/blender/editors/geometry/geometry_ops.cc
+++ b/source/blender/editors/geometry/geometry_ops.cc
@@ -22,5 +22,6 @@ void ED_operatortypes_geometry(void)
   WM_operatortype_append(GEOMETRY_OT_color_attribute_add);
   WM_operatortype_append(GEOMETRY_OT_color_attribute_remove);
   WM_operatortype_append(GEOMETRY_OT_color_attribute_render_set);
+  WM_operatortype_append(GEOMETRY_OT_color_attribute_duplicate);
   WM_operatortype_append(GEOMETRY_OT_attribute_convert);
 }