WindowManager: Support Dynamic tooltips when dragging.

Originally the operator name was drawn next to the dragging content.
After that there was an option to add custom, static text with the
dragging content. This patch allows dynamic text to be drawn.

The custom text was implemented as out parameter of the poll function
what made the code unclear. This patch introduces a tooltip function
that separates tooltip generation from the poll function.

NOTE: the text should always be returned in its own memory block. This
block will be freed after it is copied in the drag struct.

Reviewed By: Severin

Differential Revision: https://developer.blender.org/D12104

1 files changed, 80 insertions, 66 deletions

diff --git a/source/blender/editors/space_outliner/outliner_dragdrop.c b/source/blender/editors/space_outliner/outliner_dragdrop.c
index 86aab86db10..36b2966dc43 100644
--- a/source/blender/editors/space_outliner/outliner_dragdrop.c
+++ b/source/blender/editors/space_outliner/outliner_dragdrop.c
@@ -31,6 +31,7 @@
 #include "DNA_space_types.h"
 
 #include "BLI_listbase.h"
+#include "BLI_string.h"
 
 #include "BLT_translation.h"
 
@@ -316,10 +317,7 @@ static bool allow_parenting_without_modifier_key(SpaceOutliner *space_outliner)
   }
 }
 
-static bool parent_drop_poll(bContext *C,
-                             wmDrag *drag,
-                             const wmEvent *event,
-                             const char **UNUSED(r_tooltip))
+static bool parent_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
 
@@ -455,10 +453,7 @@ void OUTLINER_OT_parent_drop(wmOperatorType *ot)
 
 /* ******************** Parent Clear Operator *********************** */
 
-static bool parent_clear_poll(bContext *C,
-                              wmDrag *drag,
-                              const wmEvent *event,
-                              const char **UNUSED(r_tooltip))
+static bool parent_clear_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
 
@@ -541,10 +536,7 @@ void OUTLINER_OT_parent_clear(wmOperatorType *ot)
 
 /* ******************** Scene Drop Operator *********************** */
 
-static bool scene_drop_poll(bContext *C,
-                            wmDrag *drag,
-                            const wmEvent *event,
-                            const char **UNUSED(r_tooltip))
+static bool scene_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   /* Ensure item under cursor is valid drop target */
   Object *ob = (Object *)WM_drag_get_local_ID(drag, ID_OB);
@@ -609,10 +601,7 @@ void OUTLINER_OT_scene_drop(wmOperatorType *ot)
 
 /* ******************** Material Drop Operator *********************** */
 
-static bool material_drop_poll(bContext *C,
-                               wmDrag *drag,
-                               const wmEvent *event,
-                               const char **UNUSED(r_tooltip))
+static bool material_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   /* Ensure item under cursor is valid drop target */
   Material *ma = (Material *)WM_drag_get_local_ID(drag, ID_MA);
@@ -833,10 +822,7 @@ static bool datastack_drop_are_types_valid(StackDropData *drop_data)
   return true;
 }
 
-static bool datastack_drop_poll(bContext *C,
-                                wmDrag *drag,
-                                const wmEvent *event,
-                                const char **r_tooltip)
+static bool datastack_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   if (drag->type != WM_DRAG_DATASTACK) {
     return false;
@@ -873,33 +859,40 @@ static bool datastack_drop_poll(bContext *C,
       break;
   }
 
+  if (changed) {
+    ED_region_tag_redraw_no_rebuild(region);
+  }
+
+  return true;
+}
+
+static char *datastack_drop_tooltip(bContext *UNUSED(C),
+                                    wmDrag *drag,
+                                    const wmEvent *UNUSED(event))
+{
+  StackDropData *drop_data = drag->poin;
   switch (drop_data->drop_action) {
     case DATA_STACK_DROP_REORDER:
-      *r_tooltip = TIP_("Reorder");
+      return BLI_strdup(TIP_("Reorder"));
       break;
     case DATA_STACK_DROP_COPY:
       if (drop_data->pchan_parent) {
-        *r_tooltip = TIP_("Copy to bone");
+        return BLI_strdup(TIP_("Copy to bone"));
       }
       else {
-        *r_tooltip = TIP_("Copy to object");
+        return BLI_strdup(TIP_("Copy to object"));
       }
       break;
     case DATA_STACK_DROP_LINK:
       if (drop_data->pchan_parent) {
-        *r_tooltip = TIP_("Link all to bone");
+        return BLI_strdup(TIP_("Link all to bone"));
       }
       else {
-        *r_tooltip = TIP_("Link all to object");
+        return BLI_strdup(TIP_("Link all to object"));
       }
       break;
   }
-
-  if (changed) {
-    ED_region_tag_redraw_no_rebuild(region);
-  }
-
-  return true;
+  return NULL;
 }
 
 static void datastack_drop_link(bContext *C, StackDropData *drop_data)
@@ -1155,10 +1148,7 @@ static bool collection_drop_init(bContext *C,
   return true;
 }
 
-static bool collection_drop_poll(bContext *C,
-                                 wmDrag *drag,
-                                 const wmEvent *event,
-                                 const char **r_tooltip)
+static bool collection_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 {
   SpaceOutliner *space_outliner = CTX_wm_space_outliner(C);
   ARegion *region = CTX_wm_region(C);
@@ -1172,45 +1162,20 @@ static bool collection_drop_poll(bContext *C,
     if (!data.from || event->ctrl) {
       tselem->flag |= TSE_DRAG_INTO;
       changed = true;
-      *r_tooltip = TIP_("Link inside Collection");
     }
     else {
       switch (data.insert_type) {
         case TE_INSERT_BEFORE:
           tselem->flag |= TSE_DRAG_BEFORE;
           changed = true;
-          if (te->prev && outliner_is_collection_tree_element(te->prev)) {
-            *r_tooltip = TIP_("Move between collections");
-          }
-          else {
-            *r_tooltip = TIP_("Move before collection");
-          }
           break;
         case TE_INSERT_AFTER:
           tselem->flag |= TSE_DRAG_AFTER;
           changed = true;
-          if (te->next && outliner_is_collection_tree_element(te->next)) {
-            *r_tooltip = TIP_("Move between collections");
-          }
-          else {
-            *r_tooltip = TIP_("Move after collection");
-          }
           break;
         case TE_INSERT_INTO: {
           tselem->flag |= TSE_DRAG_INTO;
           changed = true;
-
-          /* Check the type of the drag IDs to avoid the incorrect "Shift to parent"
-           * for collections. Checking the type of the first ID works fine here since
-           * all drag IDs are the same type. */
-          wmDragID *drag_id = (wmDragID *)drag->ids.first;
-          const bool is_object = (GS(drag_id->id->name) == ID_OB);
-          if (is_object) {
-            *r_tooltip = TIP_("Move inside collection (Ctrl to link, Shift to parent)");
-          }
-          else {
-            *r_tooltip = TIP_("Move inside collection (Ctrl to link)");
-          }
           break;
         }
       }
@@ -1226,6 +1191,49 @@ static bool collection_drop_poll(bContext *C,
   return false;
 }
 
+static char *collection_drop_tooltip(bContext *C, wmDrag *drag, const wmEvent *event)
+{
+  CollectionDrop data;
+  if (!event->shift && collection_drop_init(C, drag, event, &data)) {
+    TreeElement *te = data.te;
+    if (!data.from || event->ctrl) {
+      return BLI_strdup(TIP_("Link inside Collection"));
+    }
+    switch (data.insert_type) {
+      case TE_INSERT_BEFORE:
+        if (te->prev && outliner_is_collection_tree_element(te->prev)) {
+          return BLI_strdup(TIP_("Move between collections"));
+        }
+        else {
+          return BLI_strdup(TIP_("Move before collection"));
+        }
+        break;
+      case TE_INSERT_AFTER:
+        if (te->next && outliner_is_collection_tree_element(te->next)) {
+          return BLI_strdup(TIP_("Move between collections"));
+        }
+        else {
+          return BLI_strdup(TIP_("Move after collection"));
+        }
+        break;
+      case TE_INSERT_INTO: {
+
+        /* Check the type of the drag IDs to avoid the incorrect "Shift to parent"
+         * for collections. Checking the type of the first ID works fine here since
+         * all drag IDs are the same type. */
+        wmDragID *drag_id = (wmDragID *)drag->ids.first;
+        const bool is_object = (GS(drag_id->id->name) == ID_OB);
+        if (is_object) {
+          return BLI_strdup(TIP_("Move inside collection (Ctrl to link, Shift to parent)"));
+        }
+        return BLI_strdup(TIP_("Move inside collection (Ctrl to link)"));
+        break;
+      }
+    }
+  }
+  return NULL;
+}
+
 static int collection_drop_invoke(bContext *C, wmOperator *UNUSED(op), const wmEvent *event)
 {
   Main *bmain = CTX_data_main(C);
@@ -1499,10 +1507,16 @@ void outliner_dropboxes(void)
 {
   ListBase *lb = WM_dropboxmap_find("Outliner", SPACE_OUTLINER, RGN_TYPE_WINDOW);
 
-  WM_dropbox_add(lb, "OUTLINER_OT_parent_drop", parent_drop_poll, NULL, NULL);
-  WM_dropbox_add(lb, "OUTLINER_OT_parent_clear", parent_clear_poll, NULL, NULL);
-  WM_dropbox_add(lb, "OUTLINER_OT_scene_drop", scene_drop_poll, NULL, NULL);
-  WM_dropbox_add(lb, "OUTLINER_OT_material_drop", material_drop_poll, NULL, NULL);
-  WM_dropbox_add(lb, "OUTLINER_OT_datastack_drop", datastack_drop_poll, NULL, NULL);
-  WM_dropbox_add(lb, "OUTLINER_OT_collection_drop", collection_drop_poll, NULL, NULL);
+  WM_dropbox_add(lb, "OUTLINER_OT_parent_drop", parent_drop_poll, NULL, NULL, NULL);
+  WM_dropbox_add(lb, "OUTLINER_OT_parent_clear", parent_clear_poll, NULL, NULL, NULL);
+  WM_dropbox_add(lb, "OUTLINER_OT_scene_drop", scene_drop_poll, NULL, NULL, NULL);
+  WM_dropbox_add(lb, "OUTLINER_OT_material_drop", material_drop_poll, NULL, NULL, NULL);
+  WM_dropbox_add(
+      lb, "OUTLINER_OT_datastack_drop", datastack_drop_poll, NULL, NULL, datastack_drop_tooltip);
+  WM_dropbox_add(lb,
+                 "OUTLINER_OT_collection_drop",
+                 collection_drop_poll,
+                 NULL,
+                 NULL,
+                 collection_drop_tooltip);
 }