GPv3: Keyframe on-click selection

Implementation of the click-selection operator of keyframes in the dopesheet, along with its alternatives : deselect all when no frames is hit, extend selection with shift, column selection with alt, select all keyframes on current channel with ctrl+alt.

Includes the new following API functions :
 * `select_frame_at` : selects a frame in a layer at a specific time (if such frame exists),
 * `select_all_frames` : selects all frames of a layer,
 * `select_layer_channel` : selects a layer, and sets it as active (if layer is not null, otherwise the active layer is set null),
 * `layer_has_frame_selected` : checks if any of the frames in the layer is selected.

Pull Request: https://projects.blender.org/blender/blender/pulls/110492

source/blender/blenkernel/BKE_grease_pencil.hh

@@ -499,6 +499,11 @@ inline bool GreasePencilFrame::is_implicit_hold() const
   return (this->flag & GP_FRAME_IMPLICIT_HOLD) != 0;
 }
 
+inline bool GreasePencilFrame::is_selected() const
+{
+  return (this->flag & GP_FRAME_SELECTED) != 0;
+}
+
 inline blender::bke::greasepencil::TreeNode &GreasePencilLayerTreeNode::wrap()
 {
   return *reinterpret_cast<blender::bke::greasepencil::TreeNode *>(this);

source/blender/editors/animation/anim_channels_edit.cc

@@ -32,6 +32,7 @@
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 #include "BKE_gpencil_legacy.h"
+#include "BKE_grease_pencil.hh"
 #include "BKE_layer.h"
 #include "BKE_lib_id.h"
 #include "BKE_mask.h"
@@ -593,6 +594,12 @@ static void anim_channels_select_set(bAnimContext *ac,
         }
         break;
       }
+      case ANIMTYPE_GREASE_PENCIL_LAYER: {
+        using namespace blender::bke::greasepencil;
+        Layer *layer = static_cast<Layer *>(ale->data);
+        ACHANNEL_SET_FLAG(&(layer->base), sel, GP_LAYER_TREE_NODE_SELECT);
+        break;
+      }
       case ANIMTYPE_GPLAYER: {
         bGPDlayer *gpl = (bGPDlayer *)ale->data;
 

source/blender/editors/animation/anim_filter.cc

@@ -1872,12 +1872,12 @@ static size_t animdata_filter_grease_pencil_data(ListBase *anim_data,
       /* Add data block container (if for drawing, and it contains sub-channels). */
       ANIMCHANNEL_NEW_CHANNEL(
           grease_pencil, ANIMTYPE_GREASE_PENCIL_DATABLOCK, grease_pencil, nullptr);
-
-      /* Add the list of collected channels. */
-      BLI_movelisttolist(anim_data, &tmp_data);
-      BLI_assert(BLI_listbase_is_empty(&tmp_data));
-      items += tmp_items;
     }
+
+    /* Add the list of collected channels. */
+    BLI_movelisttolist(anim_data, &tmp_data);
+    BLI_assert(BLI_listbase_is_empty(&tmp_data));
+    items += tmp_items;
   }
 
   return items;

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

@@ -6,6 +6,8 @@
  * \ingroup edgreasepencil
  */
 
+#include "BLI_map.hh"
+
 #include "BKE_context.h"
 #include "BKE_grease_pencil.hh"
 
@@ -14,6 +16,7 @@
 #include "DNA_scene_types.h"
 
 #include "ED_grease_pencil.h"
+#include "ED_keyframes_edit.h"
 
 #include "RNA_access.h"
 #include "RNA_define.h"
@@ -22,6 +25,52 @@
 
 namespace blender::ed::greasepencil {
 
+static void select_frame(GreasePencilFrame &frame, const short select_mode)
+{
+  switch (select_mode) {
+    case SELECT_ADD:
+      frame.flag |= GP_FRAME_SELECTED;
+      break;
+    case SELECT_SUBTRACT:
+      frame.flag &= ~GP_FRAME_SELECTED;
+      break;
+    case SELECT_INVERT:
+      frame.flag ^= GP_FRAME_SELECTED;
+      break;
+  }
+}
+
+bool select_frame_at(bke::greasepencil::Layer *layer,
+                     const int frame_number,
+                     const short select_mode)
+{
+
+  GreasePencilFrame *frame = layer->frames_for_write().lookup_ptr(frame_number);
+  if (frame == nullptr) {
+    return false;
+  }
+  select_frame(*frame, select_mode);
+  return true;
+}
+
+void select_all_frames(bke::greasepencil::Layer *layer, const short select_mode)
+{
+  for (auto item : layer->frames_for_write().items()) {
+    select_frame(item.value, select_mode);
+  }
+}
+
+bool layer_has_any_frame_selected(const bke::greasepencil::Layer *layer)
+{
+  for (auto item : layer->frames().items()) {
+    const GreasePencilFrame &frame = item.value;
+    if (frame.is_selected()) {
+      return true;
+    }
+  }
+  return false;
+}
+
 static int insert_blank_frame_exec(bContext *C, wmOperator *op)
 {
   using namespace blender::bke::greasepencil;

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

@@ -22,6 +22,20 @@
 
 namespace blender::ed::greasepencil {
 
+void select_layer_channel(GreasePencil *grease_pencil, bke::greasepencil::Layer *layer)
+{
+  using namespace blender::bke::greasepencil;
+
+  if (layer != nullptr) {
+    layer->base.flag |= GP_LAYER_TREE_NODE_SELECT;
+  }
+
+  if (grease_pencil->active_layer != layer) {
+    grease_pencil->set_active_layer(layer);
+    WM_main_add_notifier(NC_GPENCIL | ND_DATA | NA_EDITED, &grease_pencil);
+  }
+}
+
 static int grease_pencil_layer_add_exec(bContext *C, wmOperator *op)
 {
   using namespace blender::bke::greasepencil;

source/blender/editors/include/ED_grease_pencil.h

@@ -50,11 +50,30 @@ eAttrDomain ED_grease_pencil_selection_domain_get(struct bContext *C);
 
 #ifdef __cplusplus
 
+#  include "BKE_grease_pencil.hh"
+
 #  include "BLI_generic_span.hh"
 #  include "BLI_math_matrix_types.hh"
 
 namespace blender::ed::greasepencil {
 
+void select_layer_channel(GreasePencil *grease_pencil, bke::greasepencil::Layer *layer);
+
+/**
+ * Sets the selection flag, according to \a selection_mode to the frame at \a frame_number in the
+ * \a layer if such frame exists. Returns false if no such frame exists.
+ */
+bool select_frame_at(bke::greasepencil::Layer *layer,
+                     const int frame_number,
+                     const short select_mode);
+
+void select_all_frames(bke::greasepencil::Layer *layer, const short select_mode);
+
+/**
+ * Returns true if any frame of the \a layer is selected.
+ */
+bool layer_has_any_frame_selected(const bke::greasepencil::Layer *layer);
+
 bool active_grease_pencil_poll(bContext *C);
 bool editable_grease_pencil_poll(bContext *C);
 bool editable_grease_pencil_point_selection_poll(bContext *C);

source/blender/editors/space_action/action_select.cc

@@ -30,6 +30,7 @@
 #include "BKE_context.h"
 #include "BKE_fcurve.h"
 #include "BKE_gpencil_legacy.h"
+#include "BKE_grease_pencil.hh"
 #include "BKE_nla.h"
 
 #include "UI_interface.h"
@@ -37,6 +38,7 @@
 
 #include "ED_anim_api.h"
 #include "ED_gpencil_legacy.h"
+#include "ED_grease_pencil.h"
 #include "ED_keyframes_edit.h"
 #include "ED_keyframes_keylist.h"
 #include "ED_markers.h"
@@ -129,6 +131,11 @@ static void actkeys_list_element_to_keylist(bAnimContext *ac,
     bActionGroup *agrp = (bActionGroup *)ale->data;
     agroup_to_keylist(adt, agrp, keylist, 0);
   }
+  else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+    /* TODO: why don't we just give grease pencil layers key_data too? */
+    grease_pencil_cels_to_keylist(
+        adt, static_cast<blender::bke::greasepencil::Layer *>(ale->data), keylist, 0);
+  }
   else if (ale->type == ANIMTYPE_GPLAYER) {
     /* TODO: why don't we just give gplayers key_data too? */
     bGPDlayer *gpl = (bGPDlayer *)ale->data;
@@ -273,6 +280,14 @@ static void deselect_action_keys(bAnimContext *ac, short test, short sel)
           break;
         }
       }
+      else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+        if (blender::ed::greasepencil::layer_has_any_frame_selected(
+                static_cast<blender::bke::greasepencil::Layer *>(ale->data)))
+        {
+          sel = SELECT_SUBTRACT;
+        }
+        break;
+      }
       else {
         if (ANIM_fcurve_keyframes_loop(
                 &ked, static_cast<FCurve *>(ale->key_data), nullptr, test_cb, nullptr))
@@ -296,6 +311,11 @@ static void deselect_action_keys(bAnimContext *ac, short test, short sel)
     else if (ale->type == ANIMTYPE_MASKLAYER) {
       ED_masklayer_frame_select_set(static_cast<MaskLayer *>(ale->data), sel);
     }
+    else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+      blender::ed::greasepencil::select_all_frames(
+          static_cast<blender::bke::greasepencil::Layer *>(ale->data), sel);
+      ale->update |= ANIM_UPDATE_DEPS;
+    }
     else {
       ANIM_fcurve_keyframes_loop(
           &ked, static_cast<FCurve *>(ale->key_data), nullptr, sel_cb, nullptr);
@@ -1627,6 +1647,11 @@ static void actkeys_mselect_single(bAnimContext *ac,
     ED_gpencil_select_frame(static_cast<bGPDlayer *>(ale->data), selx, select_mode);
     ale->update |= ANIM_UPDATE_DEPS;
   }
+  else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+    blender::ed::greasepencil::select_frame_at(
+        static_cast<blender::bke::greasepencil::Layer *>(ale->data), selx, select_mode);
+    ale->update |= ANIM_UPDATE_DEPS;
+  }
   else if (ale->type == ANIMTYPE_MASKLAYER) {
     ED_mask_select_frame(static_cast<MaskLayer *>(ale->data), selx, select_mode);
   }
@@ -1692,6 +1717,11 @@ static void actkeys_mselect_column(bAnimContext *ac, short select_mode, float se
     else if (ale->type == ANIMTYPE_MASKLAYER) {
       ED_mask_select_frame(static_cast<MaskLayer *>(ale->data), selx, select_mode);
     }
+    else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+      blender::ed::greasepencil::select_frame_at(
+          static_cast<blender::bke::greasepencil::Layer *>(ale->data), selx, select_mode);
+      ale->update |= ANIM_UPDATE_DEPS;
+    }
     else {
       AnimData *adt = ANIM_nla_mapping_get(ac, ale);
 
@@ -1731,6 +1761,11 @@ static void actkeys_mselect_channel_only(bAnimContext *ac, bAnimListElem *ale, s
   else if (ale->type == ANIMTYPE_MASKLAYER) {
     ED_mask_select_frames(static_cast<MaskLayer *>(ale->data), select_mode);
   }
+  else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+    blender::ed::greasepencil::select_all_frames(
+        static_cast<blender::bke::greasepencil::Layer *>(ale->data), select_mode);
+    ale->update |= ANIM_UPDATE_DEPS;
+  }
   else {
     if (ale->type == ANIMTYPE_SUMMARY && ale->datatype == ALE_ALL) {
       ListBase anim_data = {nullptr, nullptr};
@@ -1836,10 +1871,17 @@ static int mouse_action_keys(bAnimContext *ac,
         }
       }
       else if (ac->datatype == ANIMCONT_GPENCIL) {
-        /* deselect all other channels first */
+        /* Deselect all other channels first. */
         ANIM_anim_channels_select_set(ac, ACHANNEL_SETFLAG_CLEAR);
 
-        /* Highlight GPencil Layer */
+        /* Highlight the grease pencil channel, and set the corresponding layer as active. */
+        if (ale != nullptr && ale->data != nullptr && ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+          using namespace blender::bke::greasepencil;
+          blender::ed::greasepencil::select_layer_channel(
+              reinterpret_cast<GreasePencil *>(ale->id), static_cast<Layer *>(ale->data));
+        }
+
+        /* Highlight GPencil Layer (Legacy). */
         if (ale != nullptr && ale->data != nullptr && ale->type == ANIMTYPE_GPLAYER) {
           bGPdata *gpd = (bGPdata *)ale->id;
           bGPDlayer *gpl = static_cast<bGPDlayer *>(ale->data);

source/blender/editors/transform/transform_convert_action.cc

@@ -367,6 +367,9 @@ static void createTransActionData(bContext *C, TransInfo *t)
       adt_count = count_gplayer_frames(
           static_cast<bGPDlayer *>(ale->data), t->frame_side, cfra, is_prop_edit);
     }
+    else if (ale->type == ANIMTYPE_GREASE_PENCIL_LAYER) {
+      /* GPv3: To be implemented. */
+    }
     else if (ale->type == ANIMTYPE_MASKLAYER) {
       adt_count = count_masklayer_frames(
           static_cast<MaskLayer *>(ale->data), t->frame_side, cfra, is_prop_edit);

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -156,6 +156,7 @@ typedef struct GreasePencilFrame {
   static GreasePencilFrame null();
   bool is_null() const;
   bool is_implicit_hold() const;
+  bool is_selected() const;
 #endif
 } GreasePencilFrame;