GtkRange: Fix an event propagation issue

The scale in the selectable listbox in page 2 of gtk3-widget-factory
has the flaw that the row is getting selected even when one only
interacts with the scale - unlike e.g. the checkbutton and button
further down in the listbox.

The problem is that GtkRange is trying to claim the sequence for
the drag gesture from the ::pressed handler of a multipress
gesture. Since the drag gesture hasn't seen the sequence at this
point, that is ineffective.

The fix here is to rearrange the gestures so that the multipress
gesture sees the sequence before the drag gesture, and then
claim the sequence from the ::drag-begin handler.

diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 5d0c84df604cd68d1f69a93131bf80050f1b67c3..bdf67cb4ecbda611567a70ceb392b02b3ceecf99 100644 (file)
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -226,6 +226,10 @@ static void gtk_range_multipress_gesture_released (GtkGestureMultiPress *gesture
                                                    gdouble               x,
                                                    gdouble               y,
                                                    GtkRange             *range);
+static void gtk_range_drag_gesture_begin          (GtkGestureDrag       *gesture,
+                                                   gdouble               offset_x,
+                                                   gdouble               offset_y,
+                                                   GtkRange             *range);
 static void gtk_range_drag_gesture_update         (GtkGestureDrag       *gesture,
                                                    gdouble               offset_x,
                                                    gdouble               offset_y,
@@ -756,6 +760,20 @@ gtk_range_init (GtkRange *range)
 
   _gtk_orientable_set_style_classes (GTK_ORIENTABLE (range));
 
+  /* Note: Order is important here.
+   * The ::drag-begin handler relies on the state set up by the
+   * multipress ::pressed handler. Gestures are handling events
+   * in the oppposite order in which they are added to their
+   * widget.
+   */
+  priv->drag_gesture = gtk_gesture_drag_new (GTK_WIDGET (range));
+  g_signal_connect (priv->drag_gesture, "drag-begin",
+                    G_CALLBACK (gtk_range_drag_gesture_begin), range);
+  g_signal_connect (priv->drag_gesture, "drag-update",
+                    G_CALLBACK (gtk_range_drag_gesture_update), range);
+  g_signal_connect (priv->drag_gesture, "drag-end",
+                    G_CALLBACK (gtk_range_drag_gesture_end), range);
+
   priv->multipress_gesture = gtk_gesture_multi_press_new (GTK_WIDGET (range));
   gtk_gesture_single_set_button (GTK_GESTURE_SINGLE (priv->multipress_gesture), 0);
   g_signal_connect (priv->multipress_gesture, "pressed",
@@ -763,12 +781,6 @@ gtk_range_init (GtkRange *range)
   g_signal_connect (priv->multipress_gesture, "released",
                     G_CALLBACK (gtk_range_multipress_gesture_released), range);
 
-  priv->drag_gesture = gtk_gesture_drag_new (GTK_WIDGET (range));
-  g_signal_connect (priv->drag_gesture, "drag-update",
-                    G_CALLBACK (gtk_range_drag_gesture_update), range);
-  g_signal_connect (priv->drag_gesture, "drag-end",
-                    G_CALLBACK (gtk_range_drag_gesture_end), range);
-
   priv->long_press_gesture = gtk_gesture_long_press_new (GTK_WIDGET (range));
   gtk_gesture_group (priv->drag_gesture, priv->long_press_gesture);
   g_signal_connect (priv->long_press_gesture, "pressed",
@@ -2621,8 +2633,8 @@ gtk_range_multipress_gesture_pressed (GtkGestureMultiPress *gesture,
         update_slider_position (range, x, y);
     }
 
-  if (priv->grab_location == MOUSE_SLIDER)
-    gtk_gesture_set_state (priv->drag_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
+  if (priv->grab_location == MOUSE_SLIDER);
+    /* leave it to grab-begin to claim the sequence */
   else if (priv->grab_location != MOUSE_OUTSIDE)
     gtk_gesture_set_state (priv->multipress_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
 }
@@ -2909,6 +2921,16 @@ gtk_range_drag_gesture_update (GtkGestureDrag *gesture,
     update_slider_position (range, priv->mouse_x, priv->mouse_y);
 }
 
+static void
+gtk_range_drag_gesture_begin (GtkGestureDrag *gesture,
+                              gdouble         offset_x,
+                              gdouble         offset_y,
+                              GtkRange       *range)
+{
+  if (range->priv->grab_location == MOUSE_SLIDER)
+    gtk_gesture_set_state (range->priv->drag_gesture, GTK_EVENT_SEQUENCE_CLAIMED);
+}
+
 static void
 gtk_range_drag_gesture_end (GtkGestureDrag       *gesture,
                             gdouble               offset_x,