Outliner: Avoid rebuilding tree on selection/active changes

We can avoid the rather expensive outliner tree rebuilds and only redraw
if nothing but the selection or active item changes. This should give a
bit of speedup for heavy scenes.

For this to work I had to correct a few notifiers, some were only
sending selection/active change notifiers that actually did things like
adding objects. I also added a more precise notifier type for when the
active collection changes. At the notifier subtype/action level we're
not even close to running out of bits, so this should be fine.
Also had to correct a wrong notifier check (was using `&` rather than
`==`).

1 files changed, 18 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_utils.c b/source/blender/editors/space_outliner/outliner_utils.c
index 1da44b5e51e..25dc7bc271e 100644
--- a/source/blender/editors/space_outliner/outliner_utils.c
+++ b/source/blender/editors/space_outliner/outliner_utils.c
@@ -37,6 +37,7 @@
 
 #include "ED_armature.h"
 #include "ED_outliner.h"
+#include "ED_screen.h"
 
 #include "UI_interface.h"
 #include "UI_view2d.h"
@@ -455,6 +456,23 @@ void outliner_scroll_view(ARegion *region, int delta_y)
   }
 }
 
+/**
+ * The outliner should generally use #ED_region_tag_redraw_no_rebuild() to avoid unnecessary tree
+ * rebuilds. If elements are open or closed, we may still have to rebuild.
+ * Upon changing the open/closed state, call this to avoid rebuilds if possible.
+ */
+void outliner_tag_redraw_avoid_rebuild_on_open_change(const SpaceOutliner *space_outliner,
+                                                      ARegion *region)
+{
+  /* Avoid rebuild if possible. */
+  if (outliner_mode_requires_always_rebuild(space_outliner)) {
+    ED_region_tag_redraw(region);
+  }
+  else {
+    ED_region_tag_redraw_no_rebuild(region);
+  }
+}
+
 /* Get base of object under cursor. Used for eyedropper tool */
 Base *ED_outliner_give_base_under_cursor(bContext *C, const int mval[2])
 {