Пример Drag and Drop на GTK 3

Пример из официальной документации по GTK and python 3

import gi

gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, Gdk, GdkPixbuf

(TARGET_ENTRY_TEXT, TARGET_ENTRY_PIXBUF) = range(2)
(COLUMN_TEXT, COLUMN_PIXBUF) = range(2)

DRAG_ACTION = Gdk.DragAction.COPY


class DragDropWindow(Gtk.Window):
    def __init__(self):
        Gtk.Window.__init__(self, title="Drag and Drop Demo")

        vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=6)
        self.add(vbox)

        hbox = Gtk.Box(spacing=12)
        vbox.pack_start(hbox, True, True, 0)

        self.iconview = DragSourceIconView()
        self.drop_area = DropArea()

        hbox.pack_start(self.iconview, True, True, 0)
        hbox.pack_start(self.drop_area, True, True, 0)

        button_box = Gtk.Box(spacing=6)
        vbox.pack_start(button_box, True, False, 0)

        image_button = Gtk.RadioButton.new_with_label_from_widget(None,
                                                                "Images")
        image_button.connect("toggled", self.add_image_targets)
        button_box.pack_start(image_button, True, False, 0)

        text_button = Gtk.RadioButton.new_with_label_from_widget(image_button,
                                                                "Text")
        text_button.connect("toggled", self.add_text_targets)
        button_box.pack_start(text_button, True, False, 0)

        self.add_image_targets()

    def add_image_targets(self, button=None):
        targets = Gtk.TargetList.new([])
        targets.add_image_targets(TARGET_ENTRY_PIXBUF, True)

        self.drop_area.drag_dest_set_target_list(targets)
        self.iconview.drag_source_set_target_list(targets)

    def add_text_targets(self, button=None):
        self.drop_area.drag_dest_set_target_list(None)
        self.iconview.drag_source_set_target_list(None)

        self.drop_area.drag_dest_add_text_targets()
        self.iconview.drag_source_add_text_targets()


class DragSourceIconView(Gtk.IconView):
    def __init__(self):
        Gtk.IconView.__init__(self)
        self.set_text_column(COLUMN_TEXT)
        self.set_pixbuf_column(COLUMN_PIXBUF)

        model = Gtk.ListStore(str, GdkPixbuf.Pixbuf)
        self.set_model(model)
        self.add_item("Item 1", "image-missing")
        self.add_item("Item 2", "help-about")
        self.add_item("Item 3", "edit-copy")

        self.enable_model_drag_source(Gdk.ModifierType.BUTTON1_MASK, [],
                                    DRAG_ACTION)
        self.connect("drag-data-get", self.on_drag_data_get)

    def on_drag_data_get(self, widget, drag_context, data, info, time):
        selected_path = self.get_selected_items()[0]
        selected_iter = self.get_model().get_iter(selected_path)

        if info == TARGET_ENTRY_TEXT:
            text = self.get_model().get_value(selected_iter, COLUMN_TEXT)
            data.set_text(text, -1)
        elif info == TARGET_ENTRY_PIXBUF:
            pixbuf = self.get_model().get_value(selected_iter, COLUMN_PIXBUF)
            data.set_pixbuf(pixbuf)

    def add_item(self, text, icon_name):
        pixbuf = Gtk.IconTheme.get_default().load_icon(icon_name, 16, 0)
        self.get_model().append([text, pixbuf])


class DropArea(Gtk.Label):
    def __init__(self):
        Gtk.Label.__init__(self, "Drop something on me!")
        self.drag_dest_set(Gtk.DestDefaults.ALL, [], DRAG_ACTION)

        self.connect("drag-data-received", self.on_drag_data_received)

    def on_drag_data_received(self, widget, drag_context, x, y, data, info, time):
        if info == TARGET_ENTRY_TEXT:
            text = data.get_text()
            print("Received text: %s" % text)

        elif info == TARGET_ENTRY_PIXBUF:
            pixbuf = data.get_pixbuf()
            width = pixbuf.get_width()
            height = pixbuf.get_height()

            print("Received pixbuf with width %spx and height %spx" % (width,
                                                                    height))


win = DragDropWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()

В последних версиях linux возможно потребуется изменить версию GTK на 4, для работоспособности кода.