UI: Tree-View API for easy creation of tree UIs

This follows three main targets:

* Make creation of new tree UIs easy.
* Groundwork to generalize tree UIs (so e.g. Outliner, animation
  channels, asset catalogs and spreadsheet data-sets don't have to
  re-implement basic tree UI code) or even other data-view UIs.
* Better separate data and UI state. E.g. with this, tree-item selection
  or the open/collapsed state can be stored on the UI level, rather than
  in data. (Asset Catalogs need this, storing UI state info in them is
  not an option.)

In addition, the design should be well testable and could even be
exposed to Python.

Note that things will likely change in master still. E.g. the actually
resulting UI isn't very nice visually yet.

The design is documented here:
https://wiki.blender.org/wiki/Source/Interface/Views

Differential Revision: https://developer.blender.org/D12573

1 files changed, 19 insertions, 1 deletions

diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 77ae16d7cc7..aee66ec3a93 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -384,6 +384,8 @@ typedef struct uiHandleButtonData {
   /* booleans (could be made into flags) */
   bool cancel, escapecancel;
   bool applied, applied_interactive;
+  /* Button is being applied through an extra icon. */
+  bool apply_through_extra_icon;
   bool changed_cursor;
   wmTimer *flashtimer;
 
@@ -1164,6 +1166,16 @@ static void ui_apply_but_ROW(bContext *C, uiBlock *block, uiBut *but, uiHandleBu
   data->applied = true;
 }
 
+static void ui_apply_but_TREEROW(bContext *C, uiBlock *block, uiBut *but, uiHandleButtonData *data)
+{
+  if (data->apply_through_extra_icon) {
+    /* Don't apply this, it would cause unintended tree-row toggling when clicking on extra icons.
+     */
+    return;
+  }
+  ui_apply_but_ROW(C, block, but, data);
+}
+
 /**
  * \note Ownership of \a properties is moved here. The #uiAfterFunc owns it now.
  *
@@ -2307,6 +2319,9 @@ static void ui_apply_but(
     case UI_BTYPE_ROW:
       ui_apply_but_ROW(C, block, but, data);
       break;
+    case UI_BTYPE_TREEROW:
+      ui_apply_but_TREEROW(C, block, but, data);
+      break;
     case UI_BTYPE_LISTROW:
       ui_apply_but_LISTROW(C, block, but, data);
       break;
@@ -4194,6 +4209,8 @@ static void ui_numedit_apply(bContext *C, uiBlock *block, uiBut *but, uiHandleBu
 
 static void ui_but_extra_operator_icon_apply(bContext *C, uiBut *but, uiButExtraOpIcon *op_icon)
 {
+  but->active->apply_through_extra_icon = true;
+
   if (but->active->interactive) {
     ui_apply_but(C, but->block, but, but->active, true);
   }
@@ -4737,7 +4754,7 @@ static int ui_do_but_TOG(bContext *C, uiBut *but, uiHandleButtonData *data, cons
         /* Behave like other menu items. */
         do_activate = (event->val == KM_RELEASE);
       }
-      else {
+      else if (!ui_do_but_extra_operator_icon(C, but, data, event)) {
         /* Also use double-clicks to prevent fast clicks to leak to other handlers (T76481). */
         do_activate = ELEM(event->val, KM_PRESS, KM_DBL_CLICK);
       }
@@ -7966,6 +7983,7 @@ static int ui_do_button(bContext *C, uiBlock *block, uiBut *but, const wmEvent *
     case UI_BTYPE_CHECKBOX:
     case UI_BTYPE_CHECKBOX_N:
     case UI_BTYPE_ROW:
+    case UI_BTYPE_TREEROW:
     case UI_BTYPE_DATASETROW:
       retval = ui_do_but_TOG(C, but, data, event);
       break;