GPv3: Delete grease pencil frames

Implementation of the delete frame operator for grease pencil channels.
Changes in the GreasePencil::remove_frame_at function so that it returns a boolean.

Pull Request: https://projects.blender.org/blender/blender/pulls/110746

source/blender/blenkernel/intern/grease_pencil.cc

@@ -1481,30 +1481,31 @@ bool GreasePencil::insert_duplicate_frame(blender::bke::greasepencil::Layer &lay
   return true;
 }
 
-void GreasePencil::remove_frame_at(blender::bke::greasepencil::Layer &layer,
+bool GreasePencil::remove_frame_at(blender::bke::greasepencil::Layer &layer,
                                    const int frame_number)
 {
   using namespace blender::bke::greasepencil;
   if (!layer.frames().contains(frame_number)) {
-    return;
+    return false;
   }
   const GreasePencilFrame &frame_to_remove = layer.frames().lookup(frame_number);
   const int drawing_index_to_remove = frame_to_remove.drawing_index;
   if (!layer.remove_frame(frame_number)) {
     /* If removing the frame was not successful, return early. */
-    return;
+    return false;
   }
   GreasePencilDrawingBase *drawing_base = this->drawings(drawing_index_to_remove);
   if (drawing_base->type != GP_DRAWING) {
     /* If the drawing is referenced from another object, we don't track it's users because we
      * cannot delete drawings from another object. Return early. */
-    return;
+    return false;
   }
   Drawing &drawing = reinterpret_cast<GreasePencilDrawing *>(drawing_base)->wrap();
   drawing.remove_user();
   if (!drawing.has_users()) {
     this->remove_drawing(drawing_index_to_remove);
   }
+  return true;
 }
 
 void GreasePencil::remove_drawing(const int index_to_remove)

source/blender/editors/grease_pencil/intern/grease_pencil_frames.cc

@@ -26,6 +26,19 @@
 
 namespace blender::ed::greasepencil {
 
+bool remove_all_selected_frames(GreasePencil &grease_pencil, bke::greasepencil::Layer &layer)
+{
+  bool changed = false;
+  for (auto [frame_number, frame] : layer.frames().items()) {
+    if (!frame.is_selected()) {
+      continue;
+    }
+    changed |= grease_pencil.remove_frame_at(layer, frame_number);
+  }
+
+  return changed;
+}
+
 static void select_frame(GreasePencilFrame &frame, const short select_mode)
 {
   switch (select_mode) {

source/blender/editors/include/ED_grease_pencil.h

@@ -61,6 +61,8 @@ eAttrDomain ED_grease_pencil_selection_domain_get(struct bContext *C);
 
 namespace blender::ed::greasepencil {
 
+bool remove_all_selected_frames(GreasePencil &grease_pencil, bke::greasepencil::Layer &layer);
+
 void select_layer_channel(GreasePencil *grease_pencil, bke::greasepencil::Layer *layer);
 
 /**

source/blender/editors/space_action/action_edit.cc

@@ -46,6 +46,7 @@
 
 #include "ED_anim_api.h"
 #include "ED_gpencil_legacy.h"
+#include "ED_grease_pencil.h"
 #include "ED_keyframes_edit.h"
 #include "ED_keyframing.h"
 #include "ED_markers.h"
@@ -1086,7 +1087,9 @@ static bool delete_action_keys(bAnimContext *ac)
       changed = ED_gpencil_layer_frames_delete((bGPDlayer *)ale->data);
     }
     else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
-      /* GPv3: To be implemented. */
+      changed = blender::ed::greasepencil::remove_all_selected_frames(
+          *reinterpret_cast<GreasePencil *>(ale->id),
+          static_cast<GreasePencilLayer *>(ale->data)->wrap());
     }
     else if (ale->type == ANIMTYPE_MASKLAYER) {
       changed = ED_masklayer_frames_delete((MaskLayer *)ale->data);

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -492,7 +492,7 @@ typedef struct GreasePencil {
                               const int dst_frame_number,
                               const bool do_instance);
 
-  void remove_frame_at(blender::bke::greasepencil::Layer &layer, int frame_number);
+  bool remove_frame_at(blender::bke::greasepencil::Layer &layer, int frame_number);
 
   void remove_drawing(int index);