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

4 files changed, 13 insertions, 12 deletions

diff --git a/source/blender/editors/animation/anim_channels_defines.c b/source/blender/editors/animation/anim_channels_defines.c
index 9eeabf2d05e..7dac1286526 100644
--- a/source/blender/editors/animation/anim_channels_defines.c
+++ b/source/blender/editors/animation/anim_channels_defines.c
@@ -3123,7 +3123,7 @@ static bAnimChannelType ACF_DSSIMULATION = {
 /* TODO: just get this from RNA? */
 static int acf_dsgpencil_icon(bAnimListElem *UNUSED(ale))
 {
-  return ICON_GREASEPENCIL;
+  return ICON_OUTLINER_DATA_GREASEPENCIL;
 }
 
 /* Get the appropriate flag(s) for the setting when it is valid. */
diff --git a/source/blender/editors/animation/anim_channels_edit.c b/source/blender/editors/animation/anim_channels_edit.c
index b223a1493fd..8464f280c29 100644
--- a/source/blender/editors/animation/anim_channels_edit.c
+++ b/source/blender/editors/animation/anim_channels_edit.c
@@ -2033,7 +2033,7 @@ static void setflag_anim_channels(bAnimContext *ac,
   if ((ac->spacetype == SPACE_GRAPH) && (ac->regiontype != RGN_TYPE_CHANNELS)) {
     /* graph editor (case 2) */
     filter = (ANIMFILTER_DATA_VISIBLE | ANIMFILTER_LIST_CHANNELS | ANIMFILTER_CURVE_VISIBLE |
-              ANIMFILTER_NODUPLIS);
+              ANIMFILTER_FCURVESONLY | ANIMFILTER_NODUPLIS);
   }
   else {
     /* standard case */
diff --git a/source/blender/editors/animation/anim_filter.c b/source/blender/editors/animation/anim_filter.c
index a75944fa2f2..e20932fa53e 100644
--- a/source/blender/editors/animation/anim_filter.c
+++ b/source/blender/editors/animation/anim_filter.c
@@ -1925,6 +1925,9 @@ static size_t animdata_filter_ds_gpencil(
     tmp_items += animfilter_block_data(ac, &tmp_data, ads, &gpd->id, filter_mode);
 
     /* add Grease Pencil layers */
+    if (!(filter_mode & ANIMFILTER_FCURVESONLY)) {
+      tmp_items += animdata_filter_gpencil_layers_data(&tmp_data, ads, gpd, filter_mode);
+    }
 
     /* TODO: do these need a separate expander?
      * XXX:  what order should these go in? */
diff --git a/source/blender/editors/animation/keyframes_general.c b/source/blender/editors/animation/keyframes_general.c
index 00e2f221117..30f500f9674 100644
--- a/source/blender/editors/animation/keyframes_general.c
+++ b/source/blender/editors/animation/keyframes_general.c
@@ -1217,11 +1217,11 @@ const EnumPropertyItem rna_enum_keyframe_paste_merge_items[] = {
     {0, NULL, 0, NULL, NULL},
 };
 
-short paste_animedit_keys(bAnimContext *ac,
-                          ListBase *anim_data,
-                          const eKeyPasteOffset offset_mode,
-                          const eKeyMergeMode merge_mode,
-                          bool flip)
+eKeyPasteError paste_animedit_keys(bAnimContext *ac,
+                                   ListBase *anim_data,
+                                   const eKeyPasteOffset offset_mode,
+                                   const eKeyMergeMode merge_mode,
+                                   bool flip)
 {
   bAnimListElem *ale;
 
@@ -1235,13 +1235,11 @@ short paste_animedit_keys(bAnimContext *ac,
 
   /* check if buffer is empty */
   if (BLI_listbase_is_empty(&animcopybuf)) {
-    BKE_report(ac->reports, RPT_ERROR, "No animation data in buffer to paste");
-    return -1;
+    return KEYFRAME_PASTE_NOTHING_TO_PASTE;
   }
 
   if (BLI_listbase_is_empty(anim_data)) {
-    BKE_report(ac->reports, RPT_ERROR, "No selected F-Curves to paste into");
-    return -1;
+    return KEYFRAME_PASTE_NOWHERE_TO_PASTE;
   }
 
   /* methods of offset */
@@ -1335,7 +1333,7 @@ short paste_animedit_keys(bAnimContext *ac,
 
   ANIM_animdata_update(ac, anim_data);
 
-  return 0;
+  return KEYFRAME_PASTE_OK;
 }
 
 /* **************************************************** */