Fix T83027: Incorrect outliner collection state after operator

The "Hide Collection" operators assigned to the number keys in edit mode
trigger a redraw of the outliner, but as an optimization, they do *not*
trigger a rebuild of the tree.

This optimization is valid because unlike the collection exclude toggle,
the heirarchy is not affected by collection visibility. However, it means
that currently you must trigger a rebuild to get the correct "grayed out"
status after using the operator.

Rather than trigger a rebuild in this case to solve the bug, this patch
moves the decision for whether to gray out the text of a tree element
to the draw step rather than the build step. This means that any change
to the corresponding properties doesn't require a full tree rebuild.

Note that changing the "hide_viewport" property from the outliner still
causes a tree rebuild. I think that's because of the checks in
`outliner_collection_set_flag_recursive_fn`.
That could be optimized in the future.

Differential Revision: https://developer.blender.org/D10240

source/blender/editors/space_outliner/outliner_draw.c

@@ -2958,6 +2958,41 @@ static void outliner_set_coord_tree_element(TreeElement *te, int startx, int sta
   }
 }
 
+static bool element_should_draw_faded(const TreeViewContext *tvc,
+                                      const TreeElement *te,
+                                      const TreeStoreElem *tselem)
+{
+  if (tselem->type == 0) {
+    switch (te->idcode) {
+      case ID_OB: {
+        const Object *ob = (const Object *)tselem->id;
+        /* Lookup in view layer is logically const as it only checks a cache. */
+        const Base *base = (te->directdata) ? (const Base *)te->directdata :
+                                              BKE_view_layer_base_find(
+                                                  (ViewLayer *)tvc->view_layer, (Object *)ob);
+        const bool is_visible = (base != NULL) && (base->flag & BASE_VISIBLE_VIEWLAYER);
+        if (!is_visible) {
+          return true;
+        }
+      }
+    }
+  }
+  switch (tselem->type) {
+    case TSE_LAYER_COLLECTION: {
+      const LayerCollection *layer_collection = (const LayerCollection *)te->directdata;
+      const bool is_visibe = layer_collection->runtime_flag & LAYER_COLLECTION_VISIBLE_VIEW_LAYER;
+      const bool is_excluded = layer_collection->flag & LAYER_COLLECTION_EXCLUDE;
+      return !is_visibe || is_excluded;
+    }
+  }
+
+  if (te->flag & TE_CHILD_NOT_IN_COLLECTION) {
+    return true;
+  }
+
+  return false;
+}
+
 static void outliner_draw_tree_element(bContext *C,
                                        uiBlock *block,
                                        const uiFontStyle *fstyle,
@@ -2981,10 +3016,7 @@ static void outliner_draw_tree_element(bContext *C,
   outliner_icon_background_colors(icon_bgcolor, icon_border);
 
   if (*starty + 2 * UI_UNIT_Y >= region->v2d.cur.ymin && *starty <= region->v2d.cur.ymax) {
-    const float alpha_fac = ((te->flag & TE_DISABLED) || (te->flag & TE_CHILD_NOT_IN_COLLECTION) ||
-                             draw_grayed_out) ?
-                                0.5f :
-                                1.0f;
+    const float alpha_fac = element_should_draw_faded(tvc, te, tselem) ? 0.5f : 1.0f;
     int xmax = region->v2d.cur.xmax;
 
     if ((tselem->flag & TSE_TEXTBUT) && (*te_edit == NULL)) {

source/blender/editors/space_outliner/outliner_intern.h

@@ -153,8 +153,7 @@ enum {
   TE_ICONROW = (1 << 1),
   TE_LAZY_CLOSED = (1 << 2),
   TE_FREE_NAME = (1 << 3),
-  TE_DISABLED = (1 << 4),
-  TE_DRAGGING = (1 << 5),
+  TE_DRAGGING = (1 << 4),
   TE_CHILD_NOT_IN_COLLECTION = (1 << 6),
   /* Child elements of the same type in the icon-row are drawn merged as one icon.
    * This flag is set for an element that is part of these merged child icons. */

source/blender/editors/space_outliner/tree/tree_display_view_layer.cc

@@ -143,10 +143,6 @@ void TreeDisplayViewLayer::add_layer_collections_recursive(ListBase &tree,
       if (!(tselem->used || ID_IS_LINKED(id) || ID_IS_OVERRIDE_LIBRARY(id))) {
         tselem->flag &= ~TSE_CLOSED;
       }
-
-      if (exclude || (lc->runtime_flag & LAYER_COLLECTION_VISIBLE_VIEW_LAYER) == 0) {
-        ten->flag |= TE_DISABLED;
-      }
     }
 
     add_layer_collections_recursive(ten->subtree, lc->layer_collections, *ten);
@@ -165,10 +161,6 @@ void TreeDisplayViewLayer::add_layer_collection_objects(ListBase &tree,
     TreeElement *te_object = outliner_add_element(
         &space_outliner_, &tree, base->object, &ten, 0, 0);
     te_object->directdata = base;
-
-    if (!(base->flag & BASE_VISIBLE_VIEWLAYER)) {
-      te_object->flag |= TE_DISABLED;
-    }
   }
 }