Gtk4 migration

.github/workflows/ci.yml

@@ -152,7 +152,7 @@ jobs:
  - backend: gtk
  pre-command: |
  sudo apt update -y
- sudo apt install -y pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-gtk-3.0
+ sudo apt install -y pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-gtk-3.0 libgtk-4-dev
 
  - backend: iOS
  runs-on: macos-latest
@@ -210,7 +210,7 @@ jobs:
  # tutorial, plus flwm to provide a window manager
  pre-command: |
  sudo apt update -y
- sudo apt install -y flwm pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-webkit2-4.0
+ sudo apt install -y flwm pkg-config python3-dev libgirepository1.0-dev libcairo2-dev gir1.2-webkit2-4.0 libgtk-4-dev
 
  # Start Virtual X server
  echo "Start X server..."

changes/1978.misc.rst

@@ -0,0 +1 @@
+Now, Toga is using ``Gtk4`` instead of ``Gtk3`` as the native GUI backend for Linux.

gtk/src/toga_gtk/app.py

@@ -9,10 +9,9 @@
 
 import toga
 from toga import App as toga_App
-from toga.command import GROUP_BREAK, SECTION_BREAK, Command
+from toga.command import Command
 
-from .keys import gtk_accel
-from .libs import TOGA_DEFAULT_STYLES, Gdk, Gio, GLib, Gtk
+from .libs import TOGA_DEFAULT_STYLES, Gdk, Gio, Gtk
 from .window import Window
 
 
@@ -28,13 +27,12 @@ def _handler(action, data):
 class MainWindow(Window):
  _IMPL_CLASS = Gtk.ApplicationWindow
 
- def create(self):
- super().create()
- self.native.set_role("MainWindow")
+ def __init__(self, interface, title, position, size):
+ super().__init__(interface, title, position, size)
  icon_impl = toga_App.app.icon._impl
- self.native.set_icon(icon_impl.native_72.get_pixbuf())
+ self.native.set_icon_name(icon_impl.native_72.get_icon_name())
 
- def gtk_delete_event(self, *args):
+ def gtk_close_request(self, *args):
  # Return value of the GTK on_close handler indicates
  # whether the event has been fully handled. Returning
  # False indicates the event handling is *not* complete,
@@ -47,10 +45,8 @@ def gtk_delete_event(self, *args):
 
 class App:
  """
- Todo:
- * Creation of Menus is not working.
- * Disabling of menu items is not working.
- * App Icon is not showing up
+ This is the Gtk-backed implementation of the App interface class. It is
+ the manager of all the other bits of the GUI app in Gtk-backend.
  """
 
  def __init__(self, interface):
@@ -77,6 +73,31 @@ def create(self):
 
  def gtk_startup(self, data=None):
  # Set up the default commands for the interface.
+ self._create_app_commands()
+
+ self.interface.startup()
+
+ # Create the lookup table of menu items,
+ # then force the creation of the menus.
+ self.create_menus()
+
+ # Set the default Toga styles
+ css_provider = Gtk.CssProvider()
+
+ # Backward compatibility fix for different gtk versions ===============
+ if Gtk.get_major_version() >= 4 and Gtk.get_minor_version() >= 12:
+ css_provider.load_from_string(TOGA_DEFAULT_STYLES)
+ elif Gtk.get_major_version() >= 4 and Gtk.get_minor_version() > 8:
+ css_provider.load_from_data(TOGA_DEFAULT_STYLES, len(TOGA_DEFAULT_STYLES))
+ else:
+ css_provider.load_from_data(TOGA_DEFAULT_STYLES.encode("utf-8"))
+ # =====================================================================
+
+ Gtk.StyleContext.add_provider_for_display(
+ Gdk.Display.get_default(), css_provider, Gtk.STYLE_PROVIDER_PRIORITY_USER
+ )
+
+ def _create_app_commands(self):
  self.interface.commands.add(
  Command(
  lambda _: self.interface.about(),
@@ -93,101 +114,17 @@ def gtk_startup(self, data=None):
  section=sys.maxsize,
  ),
  )
- self._create_app_commands()
-
- self.interface.startup()
-
- # Create the lookup table of menu items,
- # then force the creation of the menus.
- self.create_menus()
-
- # Now that we have menus, make the app take responsibility for
- # showing the menubar.
- # This is required because of inconsistencies in how the Gnome
- # shell operates on different windowing environments;
- # see #872 for details.
- settings = Gtk.Settings.get_default()
- settings.set_property("gtk-shell-shows-menubar", False)
-
- # Set any custom styles
- css_provider = Gtk.CssProvider()
- css_provider.load_from_data(TOGA_DEFAULT_STYLES)
-
- context = Gtk.StyleContext()
- context.add_provider_for_screen(
- Gdk.Screen.get_default(), css_provider, Gtk.STYLE_PROVIDER_PRIORITY_USER
- )
-
- def _create_app_commands(self):
- # No extra menus
- pass
 
  def gtk_activate(self, data=None):
  pass
 
  def create_menus(self):
- # Only create the menu if the menu item index has been created.
- self._menu_items = {}
- self._menu_groups = {}
-
- # Create the menu for the top level menubar.
- menubar = Gio.Menu()
- section = None
- for cmd in self.interface.commands:
- if cmd == GROUP_BREAK:
- section = None
- elif cmd == SECTION_BREAK:
- section = None
- else:
- submenu = self._submenu(cmd.group, menubar)
-
- if section is None:
- section = Gio.Menu()
- submenu.append_section(None, section)
-
- cmd_id = "command-%s" % id(cmd)
- action = Gio.SimpleAction.new(cmd_id, None)
- if cmd.action:
- action.connect("activate", gtk_menu_item_activate(cmd))
-
- cmd._impl.native.append(action)
- cmd._impl.set_enabled(cmd.enabled)
- self._menu_items[action] = cmd
- self.native.add_action(action)
-
- item = Gio.MenuItem.new(cmd.text, "app." + cmd_id)
- if cmd.shortcut:
- item.set_attribute_value(
- "accel", GLib.Variant("s", gtk_accel(cmd.shortcut))
- )
-
- section.append_item(item)
-
- # Set the menu for the app.
- self.native.set_menubar(menubar)
+ # TODO: Implementing menus in HeaderBar; See #1931.
+ self.interface.factory.not_implemented("Window.create_menus()")
+ pass
 
  def _submenu(self, group, menubar):
- try:
- return self._menu_groups[group]
- except KeyError:
- if group is None:
- submenu = menubar
- else:
- parent_menu = self._submenu(group.parent, menubar)
-
- submenu = Gio.Menu()
- self._menu_groups[group] = submenu
-
- text = group.text
- if text == "*":
- text = self.interface.name
-
- parent_menu.append_submenu(text, submenu)
-
- # Install the item in the group cache.
- self._menu_groups[group] = submenu
-
- return submenu
+ pass
 
  def main_loop(self):
  # Modify signal handlers to make sure Ctrl-C is caught and handled.
@@ -202,7 +139,7 @@ def show_about_dialog(self):
  about = Gtk.AboutDialog()
 
  icon_impl = toga_App.app.icon._impl
- about.set_logo(icon_impl.native_72.get_pixbuf())
+ about.set_logo(icon_impl.native_72.get_paintable())
 
  if self.interface.name is not None:
  about.set_program_name(self.interface.name)
@@ -215,8 +152,9 @@ def show_about_dialog(self):
  if self.interface.home_page is not None:
  about.set_website(self.interface.home_page)
 
- about.run()
- about.destroy()
+ about.set_modal(True)
+ about.set_transient_for(self.get_current_window().native)
+ about.present()
 
  def beep(self):
  Gdk.gdk_beep()