widget: Parent widgets may also consume motions

This is important when the target widget of an event is not the one that
would otherwise receive the gesture. For example, the GtkSwitch
implementation currently attaches a pan gesture to the switch itself,
but the target widget below the pointer might be the switch slider or
label.

See #1465

diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 587bf81b0fd5b02ca5215aae4a7f70a6c4eda07b..eeb5bc6423ed9bbd176d07a041b9289e187a3474 100644 (file)
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -12925,23 +12925,28 @@ _gtk_widget_consumes_motion (GtkWidget        *widget,
                              GdkEventSequence *sequence)
 {
   GtkWidgetPrivate *priv = gtk_widget_get_instance_private (widget);
-  GList *l;
-
-  g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);
 
-  for (l = priv->event_controllers; l; l = l->next)
+  while (widget != NULL && !GTK_IS_WINDOW (widget))
     {
-      GtkEventController *controller = l->data;
+      GList *l;
 
-      if (controller == NULL ||
-          !GTK_IS_GESTURE (controller))
-        continue;
+      for (l = priv->event_controllers; l; l = l->next)
+        {
+          GtkEventController *controller = l->data;
 
-      if ((!GTK_IS_GESTURE_SINGLE (controller) ||
-           GTK_IS_GESTURE_DRAG (controller) ||
-           GTK_IS_GESTURE_SWIPE (controller)) &&
-          gtk_gesture_handles_sequence (GTK_GESTURE (controller), sequence))
-        return TRUE;
+          if (controller == NULL ||
+              !GTK_IS_GESTURE (controller))
+            continue;
+
+          if ((!GTK_IS_GESTURE_SINGLE (controller) ||
+               GTK_IS_GESTURE_DRAG (controller) ||
+               GTK_IS_GESTURE_SWIPE (controller)) &&
+              gtk_gesture_handles_sequence (GTK_GESTURE (controller), sequence))
+            return TRUE;
+        }
+
+      widget = priv->parent;
+      priv = gtk_widget_get_instance_private (widget);
     }
 
   return FALSE;