[gnome-music/wip/jfelder/albumwidget-add-contextmenu] discbox: Add support for a context menu

[Jean Felder <jfelder src gnome org>]

commit a50bebdf865852bade5228d70d246a66b78c0292
Author: Jean Felder <jfelder src gnome org>
Date:   Fri Aug 6 22:26:38 2021 +0200

    discbox: Add support for a context menu
    
    right clicking on a SongWidget displays a SongWidgetMenu.

 data/ui/DiscBox.ui                      |  6 ++++++
 gnomemusic/widgets/disclistboxwidget.py | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)
---
diff --git a/data/ui/DiscBox.ui b/data/ui/DiscBox.ui
index 164d8dcbe..57df9e70e 100644
--- a/data/ui/DiscBox.ui
+++ b/data/ui/DiscBox.ui
@@ -39,4 +39,10 @@
       </object>
     </child>
   </template>
+  <object class="GtkGestureMultiPress" id="_list_box_ctrlr">
+    <property name="widget">_list_box</property>
+    <property name="propagation-phase">capture</property>
+    <property name="button">3</property>
+    <signal name="pressed" handler="_list_box_right_click" swapped="no"/>
+  </object>
 </interface>
diff --git a/gnomemusic/widgets/disclistboxwidget.py b/gnomemusic/widgets/disclistboxwidget.py
index 09f490e29..11f5fa8e7 100644
--- a/gnomemusic/widgets/disclistboxwidget.py
+++ b/gnomemusic/widgets/disclistboxwidget.py
@@ -47,6 +47,7 @@ class DiscBox(Gtk.ListBoxRow):
 
     _disc_label = Gtk.Template.Child()
     _list_box = Gtk.Template.Child()
+    _list_box_ctrlr = Gtk.Template.Child()
 
     __gsignals__ = {
         'song-activated': (GObject.SignalFlags.RUN_FIRST, None, (Gtk.Widget,))
@@ -134,6 +135,25 @@ class DiscBox(Gtk.ListBoxRow):
 
         return True
 
+    @Gtk.Template.Callback()
+    def _list_box_right_click(
+            self, gesture: Gtk.GestureMultiPress, n_press: int, x: int,
+            y: int) -> None:
+        song_widget = self._list_box.get_row_at_y(y)
+
+        _, y0 = song_widget.translate_coordinates(self._list_box, 0, 0)
+        row_height = song_widget.get_allocated_height()
+        rect = Gdk.Rectangle()
+        rect.x = x
+        rect.y = y0 + 0.5 * row_height
+
+        song_context_menu = SongWidgetMenu(
+            self._application, song_widget, self._corealbum)
+        song_context_menu.props.relative_to = self._list_box
+        song_context_menu.props.pointing_to = rect
+        song_context_menu.props.position = Gtk.PositionType.BOTTOM
+        song_context_menu.popup()
+
 
 class DiscListBox(Gtk.ListBox):
     """A ListBox widget containing all discs of a particular