Animation: Add GP layers in regular Dopesheet

Grease Pencil animation channels are now also shown in the Dopesheet
mode of the Dopesheet editor and in the Timeline.

Grease pencil related events are now listened not only by container
`SACTCONT_GPENCIL` (Grease Pencil Dopesheet), but also
`SACTCONT_DOPESHEET` (main Dopesheet), and `SACTCONT_TIMELINE`
(timeline).

A new Animation Filter flag was added: `ANIMFILTER_FCURVESONLY`. For now
this only filters out Grease Pencil Layer channels.

**Implemented:**

- Preview range set: now only considers selected Grease Pencil keyframes
  when `onlySel` parameter is true. Not only this allows the operator to
  work with grease pencil keyframes in main dopesheet, but it also fixes
  the operator in the Grease Pencil dopesheet.
- Translation: allocation (and freeing) of specific memory for
  translation of Grease Pencil keyframes.
- Copy/Paste: call to both Fcurve and GPencil operators, to allow for
  mixed selection. Errors are only reported when both the FCurve and
  GPencil functions fail to paste anything.
- Keyframe Type change and Insert Keyframe: removed some code here to
  unify Grease Pencil dopesheet and main dopesheet code.

- Jump, Snap, Mirror, Select all/box/lasso/circle, Select left/right,
  Clickselect: account for Grease Pencil channels within the channels
  loop, no need for `ANIMFILTER_FCURVESONLY` there.

**Not Implemented:**

- Graph-related operators. The filter `ANIMFILTER_FCURVESONLY` is
  naively added to all graph-related operators, meaning more-or-less all
  operators that used `ANIMFILTER_CURVE_VISIBLE`.
- Select linked: is for F-curves channel only
- Select more/less: not yet implemented for grease pencil layers.
- Clean Keys, Sample, Extrapolation, Interpolation, Easing, and Handle
  type change: work on Fcurve-channels only, so the
  `ANIMFILTER_FCURVESONLY` filter is activated

Graying out these operators (when no fcurve keyframe is selected) can be
done with custom poll functions BUT may affect performance. This is NOT
done in this patch.

**Dopesheet Summary Selection:**

The main summary of the dopesheet now also takes into account Grease
Pencil keyframes, using some nasty copy/pasting of code, as explained
[on devtalk](https://devtalk.blender.org/t/gpencil-layers-integration-in-main-dopesheet-selection-issue/24527).
It works, but may be improved, providing some deeper changes.

Reviewed By: mendio, pepeland, sybren

Maniphest Tasks: T97477

Differential Revision: https://developer.blender.org/D15003

1 files changed, 24 insertions, 9 deletions

diff --git a/source/blender/editors/gpencil/editaction_gpencil.c b/source/blender/editors/gpencil/editaction_gpencil.c
index 949043e4be1..c7d0d9e0e35 100644
--- a/source/blender/editors/gpencil/editaction_gpencil.c
+++ b/source/blender/editors/gpencil/editaction_gpencil.c
@@ -214,6 +214,18 @@ void ED_gpencil_layer_frames_select_region(KeyframeEditData *ked,
   }
 }
 
+void ED_gpencil_set_active_channel(bGPdata *gpd, bGPDlayer *gpl)
+{
+  gpl->flag |= GP_LAYER_SELECT;
+
+  /* Update other layer status. */
+  if (BKE_gpencil_layer_active_get(gpd) != gpl) {
+    BKE_gpencil_layer_active_set(gpd, gpl);
+    BKE_gpencil_layer_autolock_set(gpd, false);
+    WM_main_add_notifier(NC_GPENCIL | ND_DATA | NA_EDITED, NULL);
+  }
+}
+
 /* ***************************************** */
 /* Frame Editing Tools */
 
@@ -316,8 +328,13 @@ bool ED_gpencil_anim_copybuf_copy(bAnimContext *ac)
   filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_LIST_VISIBLE | ANIMFILTER_NODUPLIS);
   ANIM_animdata_filter(ac, &anim_data, filter, ac->data, ac->datatype);
 
-  /* assume that each of these is a GP layer */
   for (ale = anim_data.first; ale; ale = ale->next) {
+    /* This function only deals with grease pencil layer frames.
+     * This check is needed in the case of a call from the main dopesheet. */
+    if (ale->type != ANIMTYPE_GPLAYER) {
+      continue;
+    }
+
     ListBase copied_frames = {NULL, NULL};
     bGPDlayer *gpl = (bGPDlayer *)ale->data;
 
@@ -359,14 +376,8 @@ bool ED_gpencil_anim_copybuf_copy(bAnimContext *ac)
   /* clean up */
   ANIM_animdata_freelist(&anim_data);
 
-  /* check if anything ended up in the buffer */
-  if (ELEM(NULL, gpencil_anim_copybuf.first, gpencil_anim_copybuf.last)) {
-    BKE_report(ac->reports, RPT_ERROR, "No keyframes copied to keyframes copy/paste buffer");
-    return false;
-  }
-
   /* report success */
-  return true;
+  return !BLI_listbase_is_empty(&gpencil_anim_copybuf);
 }
 
 bool ED_gpencil_anim_copybuf_paste(bAnimContext *ac, const short offset_mode)
@@ -381,7 +392,6 @@ bool ED_gpencil_anim_copybuf_paste(bAnimContext *ac, const short offset_mode)
 
   /* check if buffer is empty */
   if (BLI_listbase_is_empty(&gpencil_anim_copybuf)) {
-    BKE_report(ac->reports, RPT_ERROR, "No data in buffer to paste");
     return false;
   }
 
@@ -414,6 +424,11 @@ bool ED_gpencil_anim_copybuf_paste(bAnimContext *ac, const short offset_mode)
 
   /* from selected channels */
   for (ale = anim_data.first; ale; ale = ale->next) {
+    /* only deal with GPlayers (case of calls from general dopesheet) */
+    if (ale->type != ANIMTYPE_GPLAYER) {
+      continue;
+    }
+
     bGPDlayer *gpld = (bGPDlayer *)ale->data;
     bGPDlayer *gpls = NULL;
     bGPDframe *gpfs, *gpf;