UI: Redesigned data-block selectors

The previous design is rather old and has a couple of problems:

* Scalability: The current solution of adding little icon buttons next to the
  data-block name field doesn't scale well. It only works if there's a small
  number of operations. We need to be able to place more items there for better
  data-block management. Especially with the introduction of library overrides.
* Discoverability: It's not obvious what some of the icons do. They appear and
  disappear, but it's not obvious why some are available at times and others
  not.
* Unclear Status: Currently their library status (linked, indirectly linked,
  broken link, library override) isn't really clear.
* Unusual behavior: Some of the icon buttons allow Shift or Ctrl clicking to
  invoke alternative behaviors. This is not a usual pattern in Blender.

This patch does the following changes:

* Adds a menu to the right of the name button to access all kinds of operations
  (create, delete, unlink, user management, library overrides, etc).
* Make good use of the "disabled hint" for tooltips, to explain why buttons are
  disabled. The UI team wants to establish this as a good practise.
* Use superimposed icons for duplicate and unlink, rather than extra buttons
  (uses less space, looks less distracting and is a nice + consistent design
  language).
* Remove fake user and user count button, they are available from the menu now.
* Support tooltips for superimposed icons (committed mouse hover feedback to
  master already).
* Slightly increase size of the name button - it was already a bit small
  before, and the move from real buttons to superimposed icons reduces usable
  space for the name itself.
* More clearly differentiate between duplicate and creating a new data-block.
  The latter is only available in the menu.
* Display library status icon on the left (linked, missing library, overridden,
  asset)
* Disables "Make Single User" button - in review we weren't sure if there are
  good use-cases for it, so better to see if we can remove it.

Note that I do expect some aspects of this design to change still. I think some
changes are problematic, but others disagreed. I will open a feedback thread on
devtalk to see what others think.

Differential Revision: https://developer.blender.org/D8554

Reviewed by: Bastien Montagne

Design discussed and agreed on with the UI team, also see T79959.

2 files changed, 26 insertions, 11 deletions

diff --git a/source/blender/editors/include/ED_util.h b/source/blender/editors/include/ED_util.h
index ca6b4bdc618..1e87a940a7d 100644
--- a/source/blender/editors/include/ED_util.h
+++ b/source/blender/editors/include/ED_util.h
@@ -52,10 +52,11 @@ void ED_spacedata_id_remap(struct ScrArea *area,
                            struct ID *old_id,
                            struct ID *new_id);
 
-void ED_OT_flush_edits(struct wmOperatorType *ot);
 void ED_OT_lib_id_load_custom_preview(struct wmOperatorType *ot);
 void ED_OT_lib_id_generate_preview(struct wmOperatorType *ot);
 
+void ED_operatortypes_edutils(void);
+
 /* ************** XXX OLD CRUFT WARNING ************* */
 
 void apply_keyb_grid(
diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 7c128cbf1e6..ced411ef75f 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -76,6 +76,7 @@ struct wmWindow;
 
 typedef struct uiBlock uiBlock;
 typedef struct uiBut uiBut;
+typedef struct uiButExtraOpIcon uiButExtraOpIcon;
 typedef struct uiLayout uiLayout;
 typedef struct uiPopupBlockHandle uiPopupBlockHandle;
 
@@ -1381,13 +1382,16 @@ typedef struct uiStringInfo {
 /* Note: Expects pointers to uiStringInfo structs as parameters.
  *       Will fill them with translated strings, when possible.
  *       Strings in uiStringInfo must be MEM_freeN'ed by caller. */
-void UI_but_string_info_get(struct bContext *C, uiBut *but, ...) ATTR_SENTINEL(0);
+void UI_but_string_info_get(struct bContext *C, uiBut *but, uiButExtraOpIcon *extra_icon, ...)
+    ATTR_SENTINEL(0);
 
 /* Edit i18n stuff. */
 /* Name of the main py op from i18n addon. */
 #define EDTSRC_I18N_OP_NAME "UI_OT_edittranslation"
 
 /**
+ * TODO This is old stuff, only used by templateID. Should be cleaned up.
+ *
  * Special Buttons
  *
  * Buttons with a more specific purpose:
@@ -1405,14 +1409,16 @@ enum {
   UI_ID_ALONE = 1 << 4,
   UI_ID_OPEN = 1 << 3,
   UI_ID_DELETE = 1 << 5,
-  UI_ID_LOCAL = 1 << 6,
-  UI_ID_AUTO_NAME = 1 << 7,
-  UI_ID_FAKE_USER = 1 << 8,
+  UI_ID_MAKE_LOCAL = 1 << 6,
+  UI_ID_LIB_OVERRIDE_ADD = 1 << 7,
+  UI_ID_AUTO_NAME = 1 << 8,
   UI_ID_PIN = 1 << 9,
   UI_ID_PREVIEWS = 1 << 10,
-  UI_ID_OVERRIDE = 1 << 11,
+  UI_ID_LIB_OVERRIDE_REMOVE = 1 << 11,
+  UI_ID_LIB_OVERRIDE_RESET = 1 << 12,
   UI_ID_FULL = UI_ID_RENAME | UI_ID_BROWSE | UI_ID_ADD_NEW | UI_ID_OPEN | UI_ID_ALONE |
-               UI_ID_DELETE | UI_ID_LOCAL,
+               UI_ID_DELETE | UI_ID_MAKE_LOCAL | UI_ID_LIB_OVERRIDE_ADD |
+               UI_ID_LIB_OVERRIDE_REMOVE | UI_ID_LIB_OVERRIDE_RESET,
 };
 
 /**
@@ -1658,10 +1664,12 @@ void UI_but_func_hold_set(uiBut *but, uiButHandleHoldFunc func, void *argN);
 
 void UI_but_func_pushed_state_set(uiBut *but, uiButPushedStateFunc func, void *arg);
 
-PointerRNA *UI_but_extra_operator_icon_add(uiBut *but,
-                                           const char *opname,
-                                           short opcontext,
-                                           int icon);
+struct uiButExtraOpIcon *UI_but_extra_operator_icon_add(uiBut *but,
+                                                        const char *opname,
+                                                        short opcontext,
+                                                        int icon);
+struct wmOperatorType *UI_but_extra_operator_icon_optype_get(struct uiButExtraOpIcon *extra_icon);
+PointerRNA *UI_but_extra_operator_icon_opptr_get(struct uiButExtraOpIcon *extra_icon);
 
 /* Autocomplete
  *
@@ -1963,6 +1971,7 @@ void uiTemplateID(uiLayout *layout,
                   struct PointerRNA *ptr,
                   const char *propname,
                   const char *newop,
+                  const char *duplicateop,
                   const char *openop,
                   const char *unlinkop,
                   int filter,
@@ -2567,6 +2576,11 @@ struct ARegion *UI_tooltip_create_from_button(struct bContext *C,
                                               struct ARegion *butregion,
                                               uiBut *but,
                                               bool is_label);
+struct ARegion *UI_tooltip_create_from_button_or_extra_icon(struct bContext *C,
+                                                            struct ARegion *butregion,
+                                                            uiBut *but,
+                                                            uiButExtraOpIcon *extra_icon,
+                                                            bool is_label);
 struct ARegion *UI_tooltip_create_from_gizmo(struct bContext *C, struct wmGizmo *gz);
 void UI_tooltip_free(struct bContext *C, struct bScreen *screen, struct ARegion *region);