Gesture.setSequenceState

bool setSequenceState(gdk.event_sequence.EventSequence sequence, gtk.types.EventSequenceState state)

Sets the state of sequence in gesture. Sequences start in state #GTK_EVENT_SEQUENCE_NONE, and whenever they change state, they can never go back to that state. Likewise, sequences in state #GTK_EVENT_SEQUENCE_DENIED cannot turn back to a not denied state. With these rules, the lifetime of an event sequence is constrained to the next four:

  • None
  • None → Denied
  • None → Claimed
  • None → Claimed → Denied

Note

Due to event handling ordering, it may be unsafe to

set the state on another gesture within a #GtkGesture::begin signal handler, as the callback might be executed before the other gesture knows about the sequence. A safe way to perform this could be:

static void
first_gesture_begin_cb (GtkGesture       *first_gesture,
                       GdkEventSequence *sequence,
                       gpointer          user_data)
{
 gtk_gesture_set_sequence_state (first_gesture, sequence, GTK_EVENT_SEQUENCE_CLAIMED);
 gtk_gesture_set_sequence_state (second_gesture, sequence, GTK_EVENT_SEQUENCE_DENIED);
}

static void
second_gesture_begin_cb (GtkGesture       *second_gesture,
                        GdkEventSequence *sequence,
                        gpointer          user_data)
{
 if (gtk_gesture_get_sequence_state (first_gesture, sequence) == GTK_EVENT_SEQUENCE_CLAIMED)
   gtk_gesture_set_sequence_state (second_gesture, sequence, GTK_EVENT_SEQUENCE_DENIED);
}

If both gestures are in the same group, just set the state on the gesture emitting the event, the sequence will be already be initialized to the group's global state when the second gesture processes the event.

Parameters

sequencea #GdkEventSequence
statethe sequence state

Returns

true if sequence is handled by gesture,

and the state is changed successfully