Outliner: Synced selection and active element highlighting

Adds a toggle to the filter menu for outliner synced selection. Enabled
by default, this ensures selection is synced between objects, bones, and
sequences. An active outliner element theme color is added to indicate
which element is active.

Synced selection is controlled on the operator level. Each operator
that modifies selection for objects, bones, sequences, or outliner
elements needs to call the respective ED_outliner_select_sync_from..
function to tag outliners to be synced.

Syncing is done lazily on outliner draw.

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 505042432ed..707b312e967 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -244,7 +244,12 @@ typedef struct SpaceOutliner {
   char search_string[64];
   struct TreeStoreElem search_tse;
 
-  short flag, outlinevis, storeflag, search_flags;
+  short flag, outlinevis, storeflag;
+  char search_flags;
+
+  /** Selection syncing flag (#WM_OUTLINER_SYNC_SELECT_FROM_OBJECT and similar flags). */
+  char sync_select_dirty;
+
   int filter;
   char filter_state;
   char show_restrict_flags;
@@ -263,6 +268,7 @@ typedef enum eSpaceOutliner_Flag {
   SO_FLAG_UNUSED_1 = (1 << 2), /* cleared */
   SO_HIDE_KEYINGSETINFO = (1 << 3),
   SO_SKIP_SORT_ALPHA = (1 << 4),
+  SO_SYNC_SELECT = (1 << 5),
 } eSpaceOutliner_Flag;
 
 /* SpaceOutliner.filter */