fancy fancy drag widget :o

src/ui/play_queue.vala

@@ -1,3 +1,5 @@
+// song widget+drag behavior taken from gnome music
+
 [GtkTemplate (ui = "/eu/callcc/audrey/ui/play_queue_song.ui")]
 class Ui.PlayQueueSong : Gtk.ListBoxRow {
     public bool draggable { get; set; default = false; }
@@ -57,12 +59,46 @@ class Ui.PlayQueueSong : Gtk.ListBoxRow {
         return starred == null ? "non-starred" : "starred";
     }
 
+    private double drag_x;
+    private double drag_y;
+
     [GtkCallback] private Gdk.ContentProvider? on_drag_prepare (double x, double y) {
-        if (this.draggable) return new Gdk.ContentProvider.for_value (this);
+        if (this.draggable) {
+            this.drag_x = x;
+            this.drag_y = y;
+            return new Gdk.ContentProvider.for_value (this);
+        }
         else return null;
     }
 
+    private Gtk.ListBox? drag_widget;
+
+    [GtkCallback] private void on_drag_begin (Gtk.DragSource source, Gdk.Drag drag) {
+        this.drag_widget = new Gtk.ListBox ();
+        this.drag_widget.set_size_request (this.get_width (), this.get_height ());
+
+        var drag_row = new PlayQueueSong (this.playbin);
+        drag_row.draggable = false;
+        drag_row.show_artist = this.show_artist;
+        drag_row.show_album = this.show_album;
+        drag_row.current = false;
+        drag_row.displayed_position = this.displayed_position;
+        drag_row.song = this.song;
+        drag_row.play_icon_name = this.play_icon_name;
+
+        this.drag_widget.append (drag_row);
+        this.drag_widget.drag_highlight_row (drag_row);
+
+        var drag_icon = Gtk.DragIcon.get_for_drag (drag);
+        drag_icon.set("child", this.drag_widget);
+        drag.set_hotspot ((int) this.drag_x, (int) this.drag_y);
+    }
+
     [GtkCallback] private bool on_drop (Value value, double x, double y) {
+        this.drag_widget = null;
+        this.drag_x = 0.0;
+        this.drag_y = 0.0;
+
         var source = value as PlayQueueSong;
         debug ("dropped %u on %u", source.displayed_position, this.displayed_position);
         this.playbin.move_track (source.displayed_position-1, this.displayed_position-1);

src/ui/play_queue_song.blp

@@ -124,6 +124,7 @@ template $UiPlayQueueSong: ListBoxRow {
     propagation-phase: capture;
 
     prepare => $on_drag_prepare ();
+    drag-begin => $on_drag_begin ();
   }
 
   DropTarget {