Add an action for column tooltips. It can have a shortcut.

src/calibre/customize/builtins.py

@@ -1163,6 +1163,12 @@ class ActionStore(InterfaceActionBase):
         save(config_widget)
 
 
+class ActionColumnTooltip(InterfaceActionBase):
+    name = 'Column Tooltip'
+    actual_plugin = 'calibre.gui2.actions.column_tooltips:ColumnTooltipsAction'
+    description = _('Open a template dialog to define and edit column tooltips')
+
+
 class ActionPluginUpdater(InterfaceActionBase):
     name = 'Plugin Updater'
     author = 'Grant Drake'
@@ -1170,8 +1176,8 @@ class ActionPluginUpdater(InterfaceActionBase):
     actual_plugin = 'calibre.gui2.actions.plugin_updates:PluginUpdaterAction'
 
 
-plugins += [ActionAdd, ActionAllActions, ActionFetchAnnotations, ActionGenerateCatalog,
-        ActionConvert, ActionDelete, ActionEditMetadata, ActionView,
+plugins += [ActionAdd, ActionAllActions, ActionColumnTooltip, ActionFetchAnnotations,
+        ActionGenerateCatalog, ActionConvert, ActionDelete, ActionEditMetadata, ActionView,
         ActionFetchNews, ActionSaveToDisk, ActionQuickview, ActionPolish,
         ActionShowBookDetails, ActionRestart, ActionOpenFolder, ActionConnectShare,
         ActionSendToDevice, ActionHelp, ActionPreferences, ActionSimilarBooks,

src/calibre/gui2/actions/column_tooltips.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2022, Charles Haley
+#
+
+from calibre.gui2 import error_dialog
+from calibre.gui2.actions import InterfaceAction
+from calibre.gui2.dialogs.template_dialog import TemplateDialog
+
+
+def column_template_placeholder_text():
+    return _(
+            'Notes:\n'
+            '• The template global variable "{0}" contains the column lookup name.\n'
+            '• The global variable "{1}" contains the original tooltip text').format('column_lookup_name',
+
+                                                                                     'original_text')
+class ColumnTooltipsAction(InterfaceAction):
+
+    name = 'Column tooltips'
+    action_spec = (_('Column tooltips'), 'edit_input.png',
+                   _('Define a custom tooltip for values in a column'), ())
+    action_type = 'current'
+    dont_add_to = frozenset(('context-menu-device', 'menubar-device'))
+
+    def genesis(self):
+        self.qaction.triggered.connect(self.show_template_editor)
+
+    def show_template_editor(self):
+        view = self.gui.current_view()
+        if view is not self.gui.library_view:
+            return error_dialog(self.gui, _('No template tester available'),
+                _('Template tester is not available for books '
+                  'on the device.')).exec()
+
+        idx = view.currentIndex()
+        if not idx.isValid():
+            return error_dialog(self.gui, _('No column selected'),
+                    _('A column (cell) must be selected'), show=True)
+        column = view.model().column_map[idx.column()]
+        rows = view.selectionModel().selectedRows()
+        if not rows:
+            return error_dialog(self.gui, _('No books selected'),
+                    _('At least one book must be selected'), show=True)
+        mi = []
+        db = view.model().db
+        for row in rows:
+            if row.isValid():
+                mi.append(db.new_api.get_proxy_metadata(db.data.index_to_id(row.row())))
+        if mi:
+            tt_dict = db.new_api.pref('column_tooltip_templates', {})
+            for i in range(min(len(rows), 10)):
+                mi.append(db.new_api.get_proxy_metadata(db.data.index_to_id(i)))
+            template = tt_dict.get(column, '')
+            text_is_placeholder = False
+            if not template:
+                text_is_placeholder = True
+                template = column_template_placeholder_text()
+            d = TemplateDialog(self.gui, template, mi=mi, text_is_placeholder=text_is_placeholder)
+            if d.exec():
+                tt_dict[column] = d.rule[1]
+                db.new_api.set_pref('column_tooltip_templates', tt_dict)
+
+    def location_selected(self, loc):
+        enabled = loc == 'library'
+        self.qaction.setEnabled(enabled)

src/calibre/gui2/library/views.py

@@ -574,11 +574,8 @@ class BooksView(TableView):  # {{{
             text_is_placeholder = False
             if not template:
                 text_is_placeholder = True
-                template = _(
-                    'Notes:\n'
-                    '• The template global variable "{0}" contains the column lookup name.\n'
-                    '• The global variable "{1}" contains the original tooltip text').format(
-                          'column_lookup_name', 'original_text')
+                from calibre.gui2.actions.column_tooltips import column_template_placeholder_text
+                template = column_template_placeholder_text()
             d = TemplateDialog(self, template, mi=mi, text_is_placeholder=text_is_placeholder)
             if d.exec():
                 tt_dict[column] = d.rule[1]