GPv3: Add rename function for layer groups

This adds core functions to rename layer groups while preserving
name uniqueness.

source/blender/blenkernel/BKE_grease_pencil.hh

@@ -286,10 +286,8 @@ class LayerGroup : public ::GreasePencilLayerTreeGroup {
   ~LayerGroup();
 
  public:
-  StringRefNull name() const
-  {
-    return this->base.name;
-  }
+  StringRefNull name() const;
+  void set_name(StringRefNull new_name);
 
   bool is_visible() const;
   bool is_locked() const;
@@ -374,6 +372,15 @@ class LayerGroup : public ::GreasePencilLayerTreeGroup {
   void tag_nodes_cache_dirty() const;
 };
 
+inline const TreeNode &Layer::as_node() const
+{
+  return *reinterpret_cast<const TreeNode *>(this);
+}
+inline TreeNode &Layer::as_node()
+{
+  return *reinterpret_cast<TreeNode *>(this);
+}
+
 inline StringRefNull Layer::name() const
 {
   return this->base.name;
@@ -384,13 +391,9 @@ inline LayerGroup &Layer::parent_group() const
   return this->base.parent->wrap();
 }
 
-inline const TreeNode &Layer::as_node() const
+inline StringRefNull LayerGroup::name() const
 {
-  return *reinterpret_cast<const TreeNode *>(this);
-}
-inline TreeNode &Layer::as_node()
-{
-  return *reinterpret_cast<TreeNode *>(this);
+  return this->base.name;
 }
 
 namespace convert {

source/blender/blenkernel/intern/grease_pencil.cc

@@ -616,6 +616,11 @@ LayerGroup::~LayerGroup()
   this->runtime = nullptr;
 }
 
+void LayerGroup::set_name(StringRefNull new_name)
+{
+  this->base.name = BLI_strdup(new_name.c_str());
+}
+
 bool LayerGroup::is_visible() const
 {
   if (this->base.parent) {
@@ -1406,6 +1411,19 @@ void GreasePencil::rename_layer(blender::bke::greasepencil::Layer &layer,
   layer.set_name(unique_name);
 }
 
+void GreasePencil::rename_group(blender::bke::greasepencil::LayerGroup &group,
+                                blender::StringRefNull new_name)
+{
+  using namespace blender;
+  if (group.name() == new_name) {
+    return;
+  }
+  VectorSet<StringRefNull> names = get_node_names(*this);
+  std::string unique_name(new_name.c_str());
+  unique_layer_group_name(names, unique_name.data());
+  group.set_name(unique_name);
+}
+
 void GreasePencil::remove_layer(blender::bke::greasepencil::Layer &layer)
 {
   using namespace blender::bke::greasepencil;

source/blender/editors/interface/interface_template_grease_pencil_layer_tree.cc

@@ -99,9 +99,10 @@ class LayerViewItem : public AbstractTreeViewItem {
 
 class LayerGroupViewItem : public AbstractTreeViewItem {
  public:
-  LayerGroupViewItem(/*GreasePencil &grease_pencil, */ LayerGroup &group)
-      : /*grease_pencil_(grease_pencil),*/ group_(group)
+  LayerGroupViewItem(GreasePencil &grease_pencil, LayerGroup &group)
+      : grease_pencil_(grease_pencil), group_(group)
   {
+    this->disable_activatable();
     this->label_ = group_.name();
   }
 
@@ -111,8 +112,29 @@ class LayerGroupViewItem : public AbstractTreeViewItem {
     uiItemL(sub, IFACE_(group_.name().c_str()), ICON_FILE_FOLDER);
   }
 
+  bool supports_collapsing() const override
+  {
+    return true;
+  }
+
+  bool supports_renaming() const override
+  {
+    return true;
+  }
+
+  bool rename(StringRefNull new_name) override
+  {
+    grease_pencil_.rename_group(group_, new_name);
+    return true;
+  }
+
+  StringRef get_rename_string() const override
+  {
+    return group_.name();
+  }
+
  private:
-  /* GreasePencil &grease_pencil_; */
+  GreasePencil &grease_pencil_;
   LayerGroup &group_;
 };
 
@@ -134,7 +156,9 @@ void LayerTreeView::build_tree_node_recursive(TreeNode &node)
     add_tree_item<LayerViewItem>(this->grease_pencil_, node.as_layer_for_write());
   }
   else if (node.is_group()) {
-    add_tree_item<LayerGroupViewItem>(/*this->grease_pencil_, */ node.as_group_for_write());
+    LayerGroupViewItem &group_item = parent.add_tree_item<LayerGroupViewItem>(
+        this->grease_pencil_, node.as_group_for_write());
+    group_item.set_collapsed(false);
     LISTBASE_FOREACH_BACKWARD (GreasePencilLayerTreeNode *, node_, &node.as_group().children) {
       build_tree_node_recursive(node_->wrap());
     }

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -465,6 +465,8 @@ typedef struct GreasePencil {
   blender::bke::greasepencil::Layer *find_layer_by_name(blender::StringRefNull name);
 
   void rename_layer(blender::bke::greasepencil::Layer &layer, blender::StringRefNull new_name);
+  void rename_group(blender::bke::greasepencil::LayerGroup &group,
+                    blender::StringRefNull new_name);
 
   void remove_layer(blender::bke::greasepencil::Layer &layer);