UI: Avoid rebuilding Outliner tree when opening/collapsing items

In big files, the Outliner would have a noticeable lag when opening or
collapsing items. That was because the entire tree was rebuilt, which isn't
actually needed in most cases. So we avoid it where possible now.

1 files changed, 15 insertions, 2 deletions

diff --git a/source/blender/editors/space_outliner/outliner_edit.c b/source/blender/editors/space_outliner/outliner_edit.c
index 3db75d9288b..67fa18aad86 100644
--- a/source/blender/editors/space_outliner/outliner_edit.c
+++ b/source/blender/editors/space_outliner/outliner_edit.c
@@ -191,7 +191,14 @@ static int outliner_item_openclose_modal(bContext *C, wmOperator *op, const wmEv
       /* Only toggle openclose on the same level as the first clicked element */
       if (te->xs == data->x_location) {
         outliner_item_openclose(te, data->open, false);
-        ED_region_tag_redraw(region);
+
+        /* Avoid rebuild if possible. */
+        if (outliner_element_needs_rebuild_on_open_change(TREESTORE(te))) {
+          ED_region_tag_redraw(region);
+        }
+        else {
+          ED_region_tag_redraw_no_rebuild(region);
+        }
       }
     }
 
@@ -231,7 +238,13 @@ static int outliner_item_openclose_invoke(bContext *C, wmOperator *op, const wmE
                       (toggle_all && (outliner_flag_is_any_test(&te->subtree, TSE_CLOSED, 1)));
 
     outliner_item_openclose(te, open, toggle_all);
-    ED_region_tag_redraw(region);
+    /* Avoid rebuild if possible. */
+    if (outliner_element_needs_rebuild_on_open_change(TREESTORE(te))) {
+      ED_region_tag_redraw(region);
+    }
+    else {
+      ED_region_tag_redraw_no_rebuild(region);
+    }
 
     /* Only toggle once for single click toggling */
     if (event->type == LEFTMOUSE) {