gtk: Add a custom StatusToggle button

This is a Gtk.Button that has been customized to act similarily to a
Gtk.ToggleButton, but instead of giving the button a "pressed in" look
it changes the opacity of the displayed icon.

I'm planning to use this in the window headerbar in a set of buttons
designed to controll testcase filter state.

Signed-off-by: Anna Schumaker <anna@nowheycreamery.com>

tests/gtk/test_button.py

@@ -0,0 +1,51 @@
+# Copyright 2023 (c) Anna Schumaker.
+"""Tests our custom button classes."""
+import unittest
+import xfstestsdb.gtk.button
+from gi.repository import Gtk
+
+
+class TestStatusToggle(unittest.TestCase):
+    """Test our StatusToggle button."""
+
+    def setUp(self):
+        """Set up common variables."""
+        self.button = xfstestsdb.gtk.button.StatusToggle("icon-name",
+                                                         "css-class")
+
+    def test_button(self):
+        """Test the StatusToggle button."""
+        self.assertIsInstance(self.button, Gtk.Button)
+        self.assertEqual(self.button.icon_name, "icon-name")
+        self.assertTrue(self.button.has_css_class("css-class"))
+
+        self.assertFalse(self.button.props.has_frame)
+        self.assertFalse(self.button.active)
+
+        button2 = xfstestsdb.gtk.button.StatusToggle("icon-name", "css-class",
+                                                     active=True)
+        self.assertTrue(button2.active)
+        self.assertAlmostEqual(button2.props.child.props.opacity, 1.0)
+
+    def test_image(self):
+        """Test that the image is set up correctly, and opacity changes."""
+        self.assertIsInstance(self.button.props.child, Gtk.Image)
+        self.assertEqual(self.button.props.child.props.icon_name, "icon-name")
+
+        self.button.active = True
+        self.assertAlmostEqual(self.button.props.child.props.opacity, 1.0)
+        self.button.active = False
+        self.assertAlmostEqual(self.button.props.child.props.opacity, 0.4)
+
+    def test_clicked(self):
+        """Test clicking the CSSToggle button."""
+        self.assertFalse(self.button.active)
+        self.assertAlmostEqual(self.button.props.child.props.opacity, 0.4)
+
+        self.button.emit("clicked")
+        self.assertTrue(self.button.active)
+        self.assertAlmostEqual(self.button.props.child.props.opacity, 1.0)
+
+        self.button.emit("clicked")
+        self.assertFalse(self.button.active)
+        self.assertAlmostEqual(self.button.props.child.props.opacity, 0.4)

xfstestsdb/gtk/button.py

@@ -0,0 +1,29 @@
+# Copyright 2023 (c) Anna Schumaker.
+"""Custom, reusable Button classes."""
+import typing
+from gi.repository import GObject
+from gi.repository import Gtk
+
+
+class StatusToggle(Gtk.Button):
+    """A toggle button that adds or removes a CSS class when pressed."""
+
+    active = GObject.Property(type=bool, default=False)
+    icon_name = GObject.Property(type=str)
+
+    def __init__(self, icon_name: str, css_class: str,
+                 *, active: bool = False):
+        """Initialize a StatusToggle button."""
+        super().__init__(icon_name=icon_name, has_frame=False,
+                         child=Gtk.Image(icon_name=icon_name, opacity=0.4))
+        self.connect("notify::active", self.__notify_active)
+        self.add_css_class(css_class)
+        self.active = active
+
+    def __notify_active(self, toggle: typing.Self,
+                        param: GObject.ParamSpec) -> None:
+        self.props.child.set_opacity(1.0 if self.active else 0.4)
+
+    def do_clicked(self) -> None:
+        """Adjust image opacity when the button is toggled."""
+        self.active = not self.active