Allow drag and drop of books onto formats in the Tag Browser to convert them. Fixes #1945890 [[Enhancement] Drag book to format in the Tag browser to convert it to that format](https://bugs.launchpad.net/calibre/+bug/1945890)

src/calibre/gui2/actions/convert.py

@@ -160,7 +160,15 @@ class ConvertAction(InterfaceAction):
             return
         self.do_convert(book_ids, bulk=bulk)
 
-    def do_convert(self, book_ids, bulk=None):
+    def convert_ebooks_to_format(self, book_ids, to_fmt):
+        from calibre.customize.ui import available_output_formats
+        to_fmt = to_fmt.upper()
+        if to_fmt.lower() not in available_output_formats():
+            return error_dialog(self.gui, _('Cannot convert'), _(
+                'Conversion to the {} format is not supported').format(to_fmt), show=True)
+        self.do_convert(book_ids, output_fmt=to_fmt, auto_conversion=True)
+
+    def do_convert(self, book_ids, bulk=None, auto_conversion=False, output_fmt=None):
         previous = self.gui.library_view.currentIndex()
         rows = [x.row() for x in
                 self.gui.library_view.selectionModel().selectedRows()]
@@ -168,14 +176,14 @@ class ConvertAction(InterfaceAction):
         if bulk or (bulk is None and len(book_ids) > 1):
             self.__bulk_queue = convert_bulk_ebook(self.gui, self.queue_convert_jobs,
                 self.gui.library_view.model().db, book_ids,
-                out_format=prefs['output_format'], args=(rows, previous,
+                out_format=output_fmt or prefs['output_format'], args=(rows, previous,
                     self.book_converted))
             if self.__bulk_queue is None:
                 return
             num = len(self.__bulk_queue.book_ids)
         else:
             jobs, changed, bad = convert_single_ebook(self.gui,
-                self.gui.library_view.model().db, book_ids, out_format=prefs['output_format'])
+                self.gui.library_view.model().db, book_ids, out_format=output_fmt or prefs['output_format'], auto_conversion=auto_conversion)
             self.queue_convert_jobs(jobs, changed, bad, rows, previous,
                     self.book_converted)
             num = len(jobs)

src/calibre/gui2/tag_browser/model.py

@@ -317,6 +317,7 @@ class TagsModel(QAbstractItemModel):  # {{{
     user_categories_edited = pyqtSignal(object, object)
     user_category_added = pyqtSignal()
     show_error_after_event_loop_tick_signal = pyqtSignal(object, object, object)
+    convert_requested = pyqtSignal(object, object)
 
     def __init__(self, parent, prefs=gprefs):
         QAbstractItemModel.__init__(self, parent)
@@ -977,7 +978,7 @@ class TagsModel(QAbstractItemModel):  # {{{
             if node.type == TagTreeItem.TAG:
                 fm = self.db.metadata_for_field(node.tag.category)
                 if node.tag.category in \
-                    ('tags', 'series', 'authors', 'rating', 'publisher', 'languages') or \
+                    ('tags', 'series', 'authors', 'rating', 'publisher', 'languages', 'formats') or \
                     (fm['is_custom'] and (
                             fm['datatype'] in ['text', 'rating', 'series',
                                                'enumeration'] or (
@@ -1038,9 +1039,15 @@ class TagsModel(QAbstractItemModel):  # {{{
         self.refresh_required.emit()
         self.user_category_added.emit()
 
+    def handle_drop_on_format(self, fmt, book_ids):
+        self.convert_requested.emit(book_ids, fmt)
+
     def handle_drop(self, on_node, ids):
         # print 'Dropped ids:', ids, on_node.tag
         key = on_node.tag.category
+        if key == 'formats':
+            self.handle_drop_on_format(on_node.tag.name, ids)
+            return
         if (key == 'authors' and len(ids) >= 5):
             if not confirm('<p>'+_('Changing the authors for several books can '
                            'take a while. Are you sure?') +
@@ -1393,12 +1400,13 @@ class TagsModel(QAbstractItemModel):  # {{{
                     ans |= Qt.ItemFlag.ItemIsDragEnabled
                 fm = self.db.metadata_for_field(category)
                 if category in \
-                    ('tags', 'series', 'authors', 'rating', 'publisher', 'languages') or \
+                    ('tags', 'series', 'authors', 'rating', 'publisher', 'languages', 'formats') or \
                     (fm['is_custom'] and
                         fm['datatype'] in ['text', 'rating', 'series', 'enumeration']):
                     ans |= Qt.ItemFlag.ItemIsDropEnabled
             else:
-                ans |= Qt.ItemFlag.ItemIsDropEnabled
+                if node.type != TagTreeItem.CATEGORY or node.category_key != 'formats':
+                    ans |= Qt.ItemFlag.ItemIsDropEnabled
         return ans
 
     def supportedDropActions(self):

src/calibre/gui2/tag_browser/view.py

@@ -216,9 +216,14 @@ class TagsView(QTreeView):  # {{{
         self._model.user_categories_edited.connect(self.user_categories_edited,
                 type=Qt.ConnectionType.QueuedConnection)
         self._model.drag_drop_finished.connect(self.drag_drop_finished)
+        self._model.convert_requested.connect(self.convert_requested)
         self.set_look_and_feel(first=True)
         QApplication.instance().palette_changed.connect(self.set_style_sheet, type=Qt.ConnectionType.QueuedConnection)
 
+    def convert_requested(self, book_ids, to_fmt):
+        from calibre.gui2.ui import get_gui
+        get_gui().iactions['Convert Books'].convert_ebooks_to_format(book_ids, to_fmt)
+
     def set_style_sheet(self):
         stylish_tb = '''
                 QTreeView {