Add LayoutWidget class and use it for newer widget classes

pyface/data_view/tests/test_data_view_widget.py

@@ -17,6 +17,7 @@
 
 from pyface.gui import GUI
 from pyface.toolkit import toolkit
+from pyface.testing.layout_widget_mixin import LayoutWidgetMixin
 from pyface.window import Window
 
 # This import results in an error without numpy installed
@@ -37,20 +38,7 @@
 
 
 @requires_numpy
-class TestWidget(unittest.TestCase, UnittestTools):
-
-    def setUp(self):
-        self.gui = GUI()
-
-        self.parent = Window()
-        self.parent._create()
-        self.addCleanup(self._destroy_parent)
-        self.gui.process_events()
-
-        self.widget = self._create_widget()
-
-        self.parent.open()
-        self.gui.process_events()
+class TestWidget(LayoutWidgetMixin, unittest.TestCase):
 
     def _create_widget(self):
         self.data = np.arange(120.0).reshape(4, 5, 6)
@@ -60,22 +48,6 @@ def _create_widget(self):
             data_model=self.model
         )
 
-    def _create_widget_control(self):
-        self.widget._create()
-        self.addCleanup(self._destroy_widget)
-        self.parent.show(True)
-        self.gui.process_events()
-
-    def _destroy_parent(self):
-        self.parent.destroy()
-        self.gui.process_events()
-        self.parent = None
-
-    def _destroy_widget(self):
-        self.widget.destroy()
-        self.gui.process_events()
-        self.widget = None
-
     def test_defaults(self):
         self.assertTrue(self.widget.header_visible)
 

pyface/fields/i_field.py

@@ -13,10 +13,10 @@
 
 from traits.api import Any, HasTraits, Instance, Str
 
-from pyface.i_widget import IWidget
+from pyface.i_layout_widget import ILayoutWidget
 
 
-class IField(IWidget):
+class IField(ILayoutWidget):
     """ The field interface.
 
     A field is a widget that displays a value and (potentially) allows a user

pyface/fields/tests/field_mixin.py

@@ -9,50 +9,16 @@
 # Thanks for using Enthought open source!
 
 
-from traits.testing.api import UnittestTools
+from pyface.testing.layout_widget_mixin import LayoutWidgetMixin
 
 from pyface.action.api import Action, MenuManager
 from pyface.gui import GUI
 from pyface.window import Window
 
 
-class FieldMixin(UnittestTools):
+class FieldMixin(LayoutWidgetMixin):
     """ Mixin which provides standard methods for all fields. """
 
-    def setUp(self):
-        self.gui = GUI()
-
-        self.parent = Window()
-        self.parent._create()
-        self.addCleanup(self._destroy_parent)
-        self.gui.process_events()
-
-        self.widget = self._create_widget()
-
-        self.parent.open()
-        self.gui.process_events()
-
-    def _create_widget(self):
-        raise NotImplementedError()
-
-    def _create_widget_control(self):
-        self.widget._create()
-        self.addCleanup(self._destroy_widget)
-        self.widget.show(True)
-        self.gui.process_events()
-
-    def _destroy_parent(self):
-        self.parent.destroy()
-        self.gui.process_events()
-        self.parent = None
-
-    def _destroy_widget(self):
-        self.widget.destroy()
-        self.gui.process_events()
-        self.widget = None
-
-    # Tests ------------------------------------------------------------------
-
     def test_field_tooltip(self):
         self._create_widget_control()
         self.widget.tooltip = "New tooltip."

pyface/i_layout_item.py

@@ -0,0 +1,36 @@
+# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+
+from traits.api import Enum, Int, Interface, Tuple
+
+#: Value that indicates the default size values should be used.
+DEFAULT_SIZE = -1
+
+#: Trait for sizes of widgets.
+Size = Tuple(Int(DEFAULT_SIZE), Int(DEFAULT_SIZE))
+
+#: Trait for size policy values.
+SizePolicy = Enum("default", "fixed", "preferred", "expand")
+
+
+class ILayoutItem(Interface):
+    """ An item that can participate in layout. """
+
+    #: The minimum size that the item can take.
+    minimum_size = Size
+
+    #: The maximum size that the item can take.
+    maximum_size = Size
+
+    #: Weight factor used to distribute extra space between widgets.
+    stretch = Tuple(Int, Int)
+
+    #: How the item should behave when more space is available.
+    size_policy = Tuple(SizePolicy, SizePolicy)

pyface/i_layout_widget.py

@@ -0,0 +1,183 @@
+# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+
+from traits.api import HasTraits, Int, Tuple
+
+from pyface.i_layout_item import ILayoutItem, Size, SizePolicy
+from pyface.i_widget import IWidget
+
+
+class ILayoutWidget(IWidget, ILayoutItem):
+    """ Interface for widgets that can participate in layout.
+
+    Most widgets implement ILayoutWidget, but widgets like top-level windows,
+    menus, toolbars, etc. do not.
+    """
+    pass
+
+
+class MLayoutWidget(HasTraits):
+    """ A mixin for Widgets that can participate in layouts.
+
+    Most widgets implement ILayoutWidget, but widgets like top-level windows,
+    menus, toolbars, etc. do not.
+    """
+
+    #: The minimum size that the widget can take.
+    minimum_size = Size
+
+    #: The maximum size that the widget can take.
+    maximum_size = Size
+
+    #: Weight factor used to distribute extra space between widgets.
+    stretch = Tuple(Int, Int)
+
+    #: How the widget should behave when more space is available.
+    size_policy = Tuple(SizePolicy, SizePolicy)
+
+    def _initialize_control(self):
+        """ Initialize the toolkit control. """
+        super()._initialize_control()
+        self._set_control_minimum_size(self.minimum_size)
+        self._set_control_maximum_size(self.maximum_size)
+        self._set_control_stretch(self.stretch)
+        self._set_control_size_policy(self.size_policy)
+
+    def _add_event_listeners(self):
+        """ Add trait observers and toolkit binding. """
+        super()._add_event_listeners()
+        self.observe(
+            self._minimum_size_updated,
+            "minimum_size",
+            dispatch="ui",
+        )
+        self.observe(
+            self._maximum_size_updated,
+            "maximum_size",
+            dispatch="ui",
+        )
+        self.observe(
+            self._stretch_updated,
+            "stretch",
+            dispatch="ui",
+        )
+        self.observe(
+            self._size_policy_updated,
+            "size_policy",
+            dispatch="ui",
+        )
+
+    def _remove_event_listeners(self):
+        """ Remove trait observers and toolkit binding. """
+        self.observe(
+            self._minimum_size_updated,
+            "minimum_size",
+            dispatch="ui",
+            remove=True,
+        )
+        self.observe(
+            self._maximum_size_updated,
+            "maximum_size",
+            dispatch="ui",
+            remove=True,
+        )
+        self.observe(
+            self._stretch_updated,
+            "stretch",
+            dispatch="ui",
+            remove=True,
+        )
+        self.observe(
+            self._size_policy_updated,
+            "size_policy",
+            dispatch="ui",
+            remove=True,
+        )
+        super()._remove_event_listeners()
+
+    def _minimum_size_updated(self, event):
+        """ Trait observer for minimum size. """
+        if self.control is not None:
+            self._set_control_minimum_size(event.new)
+
+    def _maximum_size_updated(self, event):
+        """ Trait observer for maximum size. """
+        if self.control is not None:
+            self._set_control_maximum_size(event.new)
+
+    def _stretch_updated(self, event):
+        """ Trait observer for stretch. """
+        if self.control is not None:
+            self._set_control_stretch(event.new)
+
+    def _size_policy_updated(self, event):
+        """ Trait observer for size policy. """
+        if self.control is not None:
+            self._set_control_size_policy(event.new)
+
+    def _set_control_minimum_size(self, size):
+        """ Set the minimum size of the control.
+
+        Toolkit implementations will need to override this method.
+        """
+        raise NotImplementedError()
+
+    def _get_control_minimum_size(self):
+        """ Get the minimum size of the control.
+
+        Toolkit implementations will need to override this method.
+        This method is only used for testing.
+        """
+        raise NotImplementedError()
+
+    def _set_control_maximum_size(self, size):
+        """ Set the maximum size of the control.
+
+        Toolkit implementations will need to override this method.
+        """
+        raise NotImplementedError()
+
+    def _get_control_maximum_size(self):
+        """ Get the maximum size of the control.
+
+        Toolkit implementations will need to override this method.
+        This method is only used for testing.
+        """
+        raise NotImplementedError()
+
+    def _set_control_stretch(self, stretch):
+        """ Set the stretch factor of the control.
+
+        Toolkit implementations will need to override this method.
+        """
+        raise NotImplementedError()
+
+    def _get_control_stretch(self):
+        """ Get the stretch factor of the control.
+
+        Toolkit implementations will need to override this method.
+        This method is only used for testing.
+        """
+        raise NotImplementedError()
+
+    def _set_control_size_policy(self, size_policy):
+        """ Set the size policy of the control.
+
+        Toolkit implementations will need to override this method.
+        """
+        raise NotImplementedError()
+
+    def _get_control_size_policy(self):
+        """ Get the size policy of the control.
+
+        Toolkit implementations will need to override this method.
+        This method is only used for testing.
+        """
+        raise NotImplementedError()

pyface/layout_widget.py

@@ -0,0 +1,15 @@
+# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+
+""" Multi-pane splitter widget. """
+
+from .toolkit import toolkit_object
+
+layout_widget = toolkit_object("layout_widget:LayoutWidget")