Elide long items in the middle when showing the completion popup for tags, to make it easier to use with hierarchical tags. Fixes #1925247 [Enhancement request: Autocomplete elision options](https://bugs.launchpad.net/calibre/+bug/1925247)

src/calibre/gui2/complete2.py

@@ -335,6 +335,9 @@ class LineEdit(QLineEdit, LineEditECM):
     @disable_popup.setter
     def disable_popup(self, val):
         self.mcompleter.disable_popup = bool(val)
+
+    def set_elide_mode(self, val):
+        self.mcompleter.setTextElideMode(val)
     # }}}
 
     def event(self, ev):
@@ -474,6 +477,9 @@ class EditWithComplete(EnComboBox):
     @disable_popup.setter
     def disable_popup(self, val):
         self.lineEdit().disable_popup = bool(val)
+
+    def set_elide_mode(self, val):
+        self.lineEdit().set_elide_mode(val)
     # }}}
 
     def text(self):

src/calibre/gui2/dialogs/metadata_bulk.py

@@ -510,7 +510,9 @@ class MetadataBulkDialog(QDialog, Ui_MetadataBulkDialog):
 
         all_tags = self.db.new_api.all_field_names('tags')
         self.tags.update_items_cache(all_tags)
+        self.tags.set_elide_mode(Qt.TextElideMode.ElideMiddle)
         self.remove_tags.update_items_cache(all_tags)
+        self.remove_tags.set_elide_mode(Qt.TextElideMode.ElideMiddle)
 
         self.initialize_combos()
 

src/calibre/gui2/library/delegates.py

@@ -358,6 +358,8 @@ class CompleteDelegate(QStyledItemDelegate, UpdateEditorGeometry):  # {{{
                     m.setData(index, self.sep.join(d.tags), Qt.ItemDataRole.EditRole)
                 return None
             editor = EditWithComplete(parent)
+            if col == 'tags':
+                editor.set_elide_mode(Qt.TextElideMode.ElideMiddle)
             editor.set_separator(self.sep)
             editor.set_space_before_sep(self.space_before_sep)
             if self.sep == '&':

src/calibre/gui2/metadata/basic_widgets.py

@@ -1379,6 +1379,7 @@ class TagsEdit(EditWithComplete, ToMetadataMixin):  # {{{
 
     def __init__(self, parent):
         EditWithComplete.__init__(self, parent)
+        self.set_elide_mode(Qt.TextElideMode.ElideMiddle)
         self.currentTextChanged.connect(self.data_changed)
         self.lineEdit().setMaxLength(655360)  # see https://bugs.launchpad.net/bugs/1630944
         self.books_to_refresh = set()