GPv3: Move dopesheet channels

This will allow to move selected channels to
Top/Bottom/Up/Down in the list.

Co-authored by: Pratik Borhade <pratikborhade302@gmail.com>

Pull Request: https://projects.blender.org/blender/blender/pulls/111009

source/blender/blenkernel/BKE_grease_pencil.hh

@@ -486,6 +486,17 @@ class LayerGroup : public ::GreasePencilLayerTreeGroup {
   Layer &add_layer_after(Layer *layer, TreeNode *link);
   Layer &add_layer_after(StringRefNull name, TreeNode *link);
 
+  /**
+   * Move child \a node up/down by \a step.
+   */
+  void move_node_up(TreeNode *node, int step = 1);
+  void move_node_down(TreeNode *node, int step = 1);
+  /**
+   * Move child \a node to the top/bottom.
+   */
+  void move_node_top(TreeNode *node);
+  void move_node_bottom(TreeNode *node);
+
   /**
    * Returns the number of direct nodes in this group.
    */

source/blender/blenkernel/intern/grease_pencil.cc

@@ -876,6 +876,29 @@ Layer &LayerGroup::add_layer_after(StringRefNull name, TreeNode *link)
   return this->add_layer_after(new_layer, link);
 }
 
+void LayerGroup::move_node_up(TreeNode *node, const int step)
+{
+  BLI_listbase_link_move(&this->children, node, step);
+  this->tag_nodes_cache_dirty();
+}
+void LayerGroup::move_node_down(TreeNode *node, const int step)
+{
+  BLI_listbase_link_move(&this->children, node, -step);
+  this->tag_nodes_cache_dirty();
+}
+void LayerGroup::move_node_top(TreeNode *node)
+{
+  BLI_remlink(&this->children, node);
+  BLI_insertlinkafter(&this->children, this->children.last, node);
+  this->tag_nodes_cache_dirty();
+}
+void LayerGroup::move_node_bottom(TreeNode *node)
+{
+  BLI_remlink(&this->children, node);
+  BLI_insertlinkbefore(&this->children, this->children.first, node);
+  this->tag_nodes_cache_dirty();
+}
+
 int64_t LayerGroup::num_direct_nodes() const
 {
   return BLI_listbase_count(&this->children);
@@ -1847,6 +1870,24 @@ blender::bke::greasepencil::Layer &GreasePencil::add_layer_after(
   return group.add_layer_after(unique_name, link);
 }
 
+void GreasePencil::move_layer_up(blender::bke::greasepencil::Layer *layer,
+                                 blender::bke::greasepencil::Layer *move_along_layer)
+{
+  layer->parent_group().unlink_node(&layer->as_node());
+  move_along_layer->parent_group().add_layer_after(layer, &move_along_layer->as_node());
+}
+
+void GreasePencil::move_layer_down(blender::Span<blender::bke::greasepencil::Layer *> layers,
+                                   blender::bke::greasepencil::Layer *move_along_layer)
+{
+  for (int i = layers.size() - 1; i >= 0; i--) {
+    using namespace blender::bke::greasepencil;
+    Layer *layer = layers[i];
+    layer->parent_group().unlink_node(&layer->as_node());
+    move_along_layer->parent_group().add_layer_before(layer, &move_along_layer->as_node());
+  }
+}
+
 blender::bke::greasepencil::Layer &GreasePencil::add_layer(const blender::StringRefNull name)
 {
   return this->add_layer(this->root_group(), name);

source/blender/editors/animation/anim_channels_edit.cc

@@ -1650,6 +1650,50 @@ static void rearrange_nla_control_channels(bAnimContext *ac,
 
 /* ------------------- */
 
+static void rearrange_grease_pencil_channels(bAnimContext *ac, eRearrangeAnimChan_Mode mode)
+{
+  using namespace blender::bke::greasepencil;
+  ListBase anim_data = {nullptr, nullptr};
+  blender::Vector<Layer *> layer_list;
+  int filter = ANIMFILTER_DATA_VISIBLE;
+
+  ANIM_animdata_filter(
+      ac, &anim_data, eAnimFilter_Flags(filter), ac->data, eAnimCont_Types(ac->datatype));
+
+  LISTBASE_FOREACH (bAnimListElem *, ale, &anim_data) {
+    Layer *layer = static_cast<Layer *>(ale->data);
+
+    switch (mode) {
+      case REARRANGE_ANIMCHAN_TOP: {
+        if (layer->is_selected()) {
+          layer->parent_group().move_node_top(&layer->as_node());
+        }
+        break;
+      }
+      case REARRANGE_ANIMCHAN_UP: {
+        if (layer->is_selected()) {
+          layer->parent_group().move_node_up(&layer->as_node());
+        }
+        break;
+      }
+      case REARRANGE_ANIMCHAN_DOWN: {
+        if (layer->is_selected()) {
+          layer->parent_group().move_node_down(&layer->as_node());
+        }
+        break;
+      }
+      case REARRANGE_ANIMCHAN_BOTTOM: {
+        if (layer->is_selected()) {
+          layer->parent_group().move_node_bottom(&layer->as_node());
+        }
+        break;
+      }
+    }
+  }
+
+  BLI_freelistN(&anim_data);
+}
+
 static void rearrange_gpencil_channels(bAnimContext *ac, eRearrangeAnimChan_Mode mode)
 {
   ListBase anim_data = {nullptr, nullptr};
@@ -1720,7 +1764,12 @@ static int animchannels_rearrange_exec(bContext *C, wmOperator *op)
   /* method to move channels depends on the editor */
   if (ac.datatype == ANIMCONT_GPENCIL) {
     /* Grease Pencil channels */
-    rearrange_gpencil_channels(&ac, mode);
+    if (U.experimental.use_grease_pencil_version3) {
+      rearrange_grease_pencil_channels(&ac, mode);
+    }
+    else {
+      rearrange_gpencil_channels(&ac, mode);
+    }
   }
   else if (ac.datatype == ANIMCONT_MASK) {
     /* Grease Pencil channels */

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -457,6 +457,12 @@ typedef struct GreasePencil {
                                                      blender::bke::greasepencil::TreeNode *link,
                                                      blender::StringRefNull name);
 
+  void move_layer_up(blender::bke::greasepencil::Layer *layer,
+                     blender::bke::greasepencil::Layer *move_along_layer);
+
+  void move_layer_down(blender::Span<blender::bke::greasepencil::Layer *> layers,
+                       blender::bke::greasepencil::Layer *move_along_layer);
+
   blender::bke::greasepencil::LayerGroup &add_layer_group(
       blender::bke::greasepencil::LayerGroup &group, blender::StringRefNull name);
   blender::bke::greasepencil::LayerGroup &add_layer_group(blender::StringRefNull name);