kinetic-scroll-view: Make it exclusive to pointer/single-touch

If we receive touch events, obey a single sequence and cancel all
operations if more are received.

The return value in the event handlers has been changed so the
event is propagated, and kinetic scroll can work in cooperation
with pinch/zoom gestures.

https://bugzilla.gnome.org/show_bug.cgi?id=709606

1 files changed, 39 insertions, 6 deletions

diff --git a/champlain/champlain-kinetic-scroll-view.c b/champlain/champlain-kinetic-scroll-view.c
index 20867ff..d210aea 100644
--- a/champlain/champlain-kinetic-scroll-view.c
+++ b/champlain/champlain-kinetic-scroll-view.c
@@ -57,6 +57,7 @@ struct _ChamplainKineticScrollViewPrivate
   gdouble decel_rate;
 
   ClutterActor *viewport;
+  ClutterEventSequence *sequence;
 };
 
 enum
@@ -259,7 +260,7 @@ motion_event_cb (ClutterActor *stage,
   gfloat x, y;
 
   if ((event->type != CLUTTER_MOTION || !(event->modifier_state & CLUTTER_BUTTON1_MASK)) &&
-      event->type != CLUTTER_TOUCH_UPDATE)
+      (event->type != CLUTTER_TOUCH_UPDATE || priv->sequence != clutter_event_get_event_sequence ((ClutterEvent *) event)))
     return FALSE;
 
   if (clutter_actor_transform_stage_point (actor,
@@ -310,7 +311,7 @@ motion_event_cb (ClutterActor *stage,
       g_get_current_time (&motion->time);
     }
 
-  return TRUE;
+  return FALSE;
 }
 
 
@@ -390,10 +391,9 @@ button_release_event_cb (ClutterActor *stage,
   ClutterActor *actor = CLUTTER_ACTOR (scroll);
   gboolean decelerating = FALSE;
 
-
   if ((event->type != CLUTTER_MOTION || event->modifier_state & CLUTTER_BUTTON1_MASK) &&
       (event->type != CLUTTER_BUTTON_RELEASE || event->button != 1) && 
-      event->type != CLUTTER_TOUCH_END)
+      (event->type != CLUTTER_TOUCH_END || priv->sequence != clutter_event_get_event_sequence ((ClutterEvent *) event)))
     return FALSE;
 
   g_signal_handlers_disconnect_by_func (stage,
@@ -567,6 +567,8 @@ button_release_event_cb (ClutterActor *stage,
         }
     }
 
+  priv->sequence = NULL;
+
   /* Reset motion event buffer */
   priv->last_motion = 0;
 
@@ -576,7 +578,12 @@ button_release_event_cb (ClutterActor *stage,
       g_signal_emit_by_name (scroll, "panning-completed", NULL);
     }
 
-  return TRUE;
+  /* Due to the way gestures in progress connect to the stage in order to
+   * receive events, we must let these events go through, as they could be
+   * essential for the management of the ClutterZoomGesture in the
+   * ChamplainView.
+   */
+  return FALSE;
 }
 
 
@@ -589,8 +596,27 @@ button_press_event_cb (ClutterActor *actor,
   ClutterButtonEvent *bevent = (ClutterButtonEvent *) event;
   ClutterActor *stage = clutter_actor_get_stage (actor);
 
+  if (event->type == CLUTTER_TOUCH_BEGIN && priv->sequence)
+    {
+      /* On multi touch input, shy away an cancel everything */
+      priv->sequence = NULL;
+
+      g_signal_handlers_disconnect_by_func (stage,
+          motion_event_cb,
+          scroll);
+      g_signal_handlers_disconnect_by_func (stage,
+          button_release_event_cb,
+          scroll);
+
+      champlain_kinetic_scroll_view_stop (scroll);
+      clamp_adjustments (scroll);
+      g_signal_emit_by_name (scroll, "panning-completed", NULL);
+
+      return FALSE;
+    }
+
   if ((((event->type == CLUTTER_BUTTON_PRESS) && (bevent->button == 1)) ||
-      event->type == CLUTTER_TOUCH_BEGIN) &&
+      (event->type == CLUTTER_TOUCH_BEGIN && !priv->sequence)) &&
       stage)
     {
       ChamplainKineticScrollViewMotion *motion;
@@ -611,6 +637,8 @@ button_press_event_cb (ClutterActor *actor,
               priv->deceleration_timeline = NULL;
             }
 
+          priv->sequence = clutter_event_get_event_sequence (event);
+
           g_signal_connect (stage,
               "captured-event",
               G_CALLBACK (motion_event_cb),
@@ -622,6 +650,11 @@ button_press_event_cb (ClutterActor *actor,
         }
     }
 
+  /* Due to the way gestures in progress connect to the stage in order to
+   * receive events, we must let these events go through, as they could be
+   * essential for the management of the ClutterZoomGesture in the
+   * ChamplainView.
+   */
   return FALSE;
 }