virtual bool UpdateFromParentTime (TimeSpan parentTime)
{
bool rv = Clock::UpdateFromParentTime (parentTime);
bool children_rv = false;
for (GList *l = child_clocks; l; l = l->next) {
Clock *clock = (Clock*)l->data;
children_rv = clock->UpdateFromParentTime (current_time) || children_rv;
}
return rv && children_rv;
}
bool
ClockGroup::UpdateFromParentTime (TimeSpan parentTime)
{
// we need to cache this here because
// Clock::UpdateFromParentTime will be updating it for the
// next tick.
ClockState current_state = GetClockState();
/* likewise, we need to cache this here since
Clock::UpdateFromParentTime will clear it */
bool seeking = GetIsSeeking();
bool rv = Clock::UpdateFromParentTime (parentTime);
// ClockGroups (which correspond to storyboards generally)
// only cause their children to update (and therefore for
// animations to hold/progress their value) if they are
// active, or if they've had Seek called on them.
//
// but it also happens when the clockgroup is in the Filling
// state. This means that you can attach a handler to
// Storyboard.Completed and inside the handler modify a
// property that an animation under that storyboard was
// targetting. and the new setting isnt clobbered by the
// animation like it would be if the storyboard was active.
bool update_child_clocks = (current_state == Clock::Active || seeking);
for (GList *l = child_clocks; l; l = l->next) {
Clock *clock = (Clock*)l->data;
if (update_child_clocks || clock->Is(Type::CLOCKGROUP))
rv = clock->UpdateFromParentTime (current_time) || rv;
}
return rv;
}