Port 'Scrolled Window' demo to Python (#59)

demos/Scrolled Window/main.py

@@ -0,0 +1,109 @@
+import gi
+
+gi.require_version("Gtk", "4.0")
+gi.require_version("Adw", "1")
+
+from gi.repository import Gtk, Adw
+import workbench
+
+scrolled_window = workbench.builder.get_object("scrolled_window")
+container = workbench.builder.get_object("container")
+toggle_orientation = workbench.builder.get_object("toggle_orientation")
+button_start = workbench.builder.get_object("button_start")
+button_end = workbench.builder.get_object("button_end")
+auto_scrolling = False
+
+button_start.sensitive = False
+
+scrollbars = {
+    Gtk.Orientation.HORIZONTAL: scrolled_window.get_hscrollbar(),
+    Gtk.Orientation.VERTICAL: scrolled_window.get_vscrollbar(),
+}
+
+
+def on_toggled(_button):
+    if toggle_orientation.get_active():
+        container.set_orientation(Gtk.Orientation.HORIZONTAL)
+    else:
+        container.set_orientation(Gtk.Orientation.VERTICAL)
+
+
+def on_animation_done(_animation):
+    global auto_scrolling
+    auto_scrolling = False
+
+
+def create_scrollbar_anim(scrollbar, direction):
+    # direction = 0 -> Animates to Start
+    # direction = 1 -> Animates to End
+    adjustment = scrollbar.get_adjustment()
+    target = Adw.PropertyAnimationTarget.new(adjustment, "value")
+    animation = Adw.TimedAnimation(
+        widget=scrollbar,
+        value_from=adjustment.get_value(),
+        value_to=adjustment.get_upper() - adjustment.get_page_size()
+        if direction
+        else 0,
+        duration=1000,
+        easing=Adw.Easing.LINEAR,
+        target=target,
+    )
+
+    animation.connect("done", on_animation_done)
+    return animation
+
+
+def on_button_clicked(_button, direction):
+    global auto_scrolling
+    auto_scrolling = True
+    scrollbar = scrollbars[container.get_orientation()]
+    anim = create_scrollbar_anim(scrollbar, direction)
+    anim.play()
+
+
+def populate_container(container, label):
+    item = Adw.Bin(
+        margin_top=6,
+        margin_bottom=6,
+        margin_start=6,
+        margin_end=6,
+        child=Gtk.Label(
+            label=label,
+            width_request=100,
+            height_request=100,
+        ),
+        css_classes=["card"],
+    )
+    container.append(item)
+
+
+def on_value_changed(adj):
+    if adj.get_value() == adj.get_lower():
+        button_end.set_sensitive(True)
+        button_start.set_sensitive(False)
+    elif adj.get_value() == adj.get_upper() - adj.get_page_size():
+        button_end.set_sensitive(False)
+        button_start.set_sensitive(True)
+    else:
+        # Disable buttons if scrollbar is auto-scrolling
+        button_end.set_sensitive(not auto_scrolling)
+        button_start.set_sensitive(not auto_scrolling)
+
+
+toggle_orientation.connect("toggled", on_toggled)
+
+num_items = 20
+for i in range(num_items):
+    populate_container(container, f"Item {i + 1}")
+
+
+for _orientation, scrollbar in scrollbars.items():
+    adj = scrollbar.get_adjustment()
+    adj.connect("value-changed", on_value_changed)
+
+scrolled_window.connect(
+    "edge-reached", lambda _window, _position: print("Edge Reached")
+)
+
+button_start.connect("clicked", on_button_clicked, 0)
+button_end.connect("clicked", on_button_clicked, 1)