Outliner: walk navigation operator and openclose fixes

Adds a keyboard walk navigation and selection operator to the
outliner. Up and down arrow keys walk up and down the list of
elements, and left and right will open and close elements if
the elements are closed or opened respectively. Holding shift
while walking up and down the tree expands the selection.

Holding shift while clicking or pressing left and right arrows
will expand or collapse all children elements recursively.
Pressing enter to openclose the hovered element is removed.

Also allows click+drag for openclose of element subtrees.

This moves openclose toggling to the openclose operator to
remove duplicate code. The outliner tree building is tweaked
slightly to set the proper parents in scene display mode for walk
select to walk to parents without errors.

1 files changed, 56 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_utils.c b/source/blender/editors/space_outliner/outliner_utils.c
index d39a9387a6a..5dfdf6f129b 100644
--- a/source/blender/editors/space_outliner/outliner_utils.c
+++ b/source/blender/editors/space_outliner/outliner_utils.c
@@ -327,12 +327,68 @@ float outliner_restrict_columns_width(const SpaceOutliner *soops)
   return (num_columns * UI_UNIT_X + V2D_SCROLL_WIDTH);
 }
 
+/* Find first tree element in tree with matching treestore flag */
+TreeElement *outliner_find_element_with_flag(const ListBase *lb, short flag)
+{
+  for (TreeElement *te = lb->first; te; te = te->next) {
+    if ((TREESTORE(te)->flag & flag) == flag) {
+      return te;
+    }
+    TreeElement *active_element = outliner_find_element_with_flag(&te->subtree, flag);
+    if (active_element) {
+      return active_element;
+    }
+  }
+  return NULL;
+}
+
+/* Find if element is visible in the outliner tree */
+bool outliner_is_element_visible(const TreeElement *te)
+{
+  TreeStoreElem *tselem;
+
+  while (te->parent) {
+    tselem = TREESTORE(te->parent);
+
+    if (tselem->flag & TSE_CLOSED) {
+      return false;
+    }
+    else {
+      te = te->parent;
+    }
+  }
+
+  return true;
+}
+
 /* Find if x coordinate is over element disclosure toggle */
 bool outliner_item_is_co_within_close_toggle(TreeElement *te, float view_co_x)
 {
   return (view_co_x > te->xs) && (view_co_x < te->xs + UI_UNIT_X);
 }
 
+/* Scroll view vertically while keeping within total bounds */
+void outliner_scroll_view(ARegion *ar, int delta_y)
+{
+  int y_min = MIN2(ar->v2d.cur.ymin, ar->v2d.tot.ymin);
+
+  ar->v2d.cur.ymax += delta_y;
+  ar->v2d.cur.ymin += delta_y;
+
+  /* Adjust view if delta placed view outside total area */
+  int offset;
+  if (ar->v2d.cur.ymax > -UI_UNIT_Y) {
+    offset = ar->v2d.cur.ymax;
+    ar->v2d.cur.ymax -= offset;
+    ar->v2d.cur.ymin -= offset;
+  }
+  else if (ar->v2d.cur.ymin < y_min) {
+    offset = y_min - ar->v2d.cur.ymin;
+    ar->v2d.cur.ymax += offset;
+    ar->v2d.cur.ymin += offset;
+  }
+}
+
 /* Get base of object under cursor. Used for eyedropper tool */
 Base *ED_outliner_give_base_under_cursor(bContext *C, const int mval[2])
 {