Fix main window positioning

openlp/core/ui/mainwindow.py

@@ -1234,6 +1234,8 @@ class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow, LogMixin, RegistryPropert
         self.move(self.settings.value('user interface/main window position'))
         self.restoreGeometry(self.settings.value('user interface/main window geometry'))
         self.restoreState(self.settings.value('user interface/main window state'))
+        if not self._window_position_is_valid(self.pos(), self.geometry()):
+            self.move(0, 0)
         self.live_controller.splitter.restoreState(self.settings.value('user interface/live splitter geometry'))
         self.preview_controller.splitter.restoreState(self.settings.value('user interface/preview splitter geometry'))
         self.control_splitter.restoreState(self.settings.value('user interface/main window splitter geometry'))
@@ -1241,6 +1243,29 @@ class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow, LogMixin, RegistryPropert
         # which was True (by default) < OpenLP 2.1.
         self.control_splitter.setChildrenCollapsible(False)
 
+    def _window_position_is_valid(self, position, geometry):
+        """
+        Checks if the saved window position is still valid by checking if the bar at the top of the window
+        (which allows the user to move the window) appears on one of the screens.
+        This may not be the case if the user has unplugged the monitor where openlp was previously shown,
+        or if the displays have been reconfigured.
+
+        :param position: QtCore.QtPoint for the top left position of the window
+        :param geometry: QtCore.QRect for the geometry of the window
+
+        :return:    True or False
+        """
+        screens = ScreenList()
+        for screen in screens:
+            # window top bar y value must be between top and bottom of a screen
+            # plus the left edge must be left of the right of the screen
+            # and the right edge must be right of the left of the screen (allowing 50 pixels for control buttons)
+            if ((screen.geometry.y() <= position.y() <= screen.geometry.y() + screen.geometry.height()) and
+                    (position.x() < screen.geometry.x() + screen.geometry.width()) and
+                    (position.x() + geometry.width() > screen.geometry.x() + 50)):
+                return True
+        return False
+
     def save_settings(self):
         """
         Save the main window settings.

tests/openlp_core/ui/test_mainwindow.py

@@ -174,6 +174,69 @@ def test_set_service_unmodified(main_window):
         'The main window\'s title should be set to "<the contents of UiStrings().OpenLP> - test.osz"'
 
 
+def test_load_settings_position_valid(main_window, settings):
+    """
+    Test that the position of the main window is restored when it's valid
+    """
+    # GIVEN a newly opened OpenLP instance, mocked screens and settings for a valid window position
+    # mock out some other calls in load_settings()
+    main_window.control_splitter = MagicMock()
+    main_window._live_controller = MagicMock()
+    main_window._preview_controller = MagicMock()
+    # set up a window position and geometry to use in the settings
+    main_window.move(QtCore.QPoint(10, 10))
+    main_window.resize(1000, 500)
+    # need to call show() to ensure the geometry works as expected
+    # unfortunately this seems to work on Windows only, not on linux
+    main_window.show()
+    main_window.hide()
+    # store the values in the settings
+    settings.setValue('user interface/main window position', main_window.pos())
+    settings.setValue('user interface/main window geometry', main_window.saveGeometry())
+    settings.setValue('user interface/main window state', main_window.saveState())
+    # change the position and size - then we can test if load_settings() sets it back correctly
+    main_window.move(QtCore.QPoint(20, 20))
+    main_window.resize(500, 300)
+
+    # WHEN the settings are loaded
+    main_window.load_settings()
+
+    # THEN the main window's position and geometry should be set to the saved setting
+    # on linux the tests works for the x position only
+    assert main_window.pos().x() == 10
+
+
+def test_load_settings_position_invalid(main_window, settings):
+    """
+    Test that the position of the main window is not restored when it's invalid, but rather set to (0, 0)
+    """
+    # GIVEN a newly opened OpenLP instance, mocked screens and settings for a valid window position
+    # mock out some other calls in load_settings()
+    main_window.control_splitter = MagicMock()
+    main_window._live_controller = MagicMock()
+    main_window._preview_controller = MagicMock()
+    # set up a window position outside the parameters of the main_window fixture
+    # this can represent a monitor positioned above the primary display, but which has been unplugged
+    main_window.move(QtCore.QPoint(-100, -800))
+    main_window.resize(1000, 500)
+    # need to call show() to ensure the geometry works as expected (works on Windows, but not linux)
+    main_window.show()
+    main_window.hide()
+    # store the values in the settings
+    settings.setValue('user interface/main window position', main_window.pos())
+    settings.setValue('user interface/main window geometry', main_window.saveGeometry())
+    settings.setValue('user interface/main window state', main_window.saveState())
+    # change the position and size
+    main_window.move(QtCore.QPoint(20, 20))
+    main_window.resize(500, 300)
+
+    # WHEN the settings are loaded
+    main_window.load_settings()
+
+    # THEN the main window's position should be (0, 0)
+    assert main_window.pos().x() == 0
+
+
 def test_mainwindow_configuration(main_window):
     """
     Check that the Main Window initialises the Registry Correctly