internal static void BeginAnimation(
DependencyObject d,
DependencyProperty dp,
AnimationTimeline animation,
HandoffBehavior handoffBehavior)
{
// Caller should be validating animation.
Debug.Assert(animation == null || IsAnimationValid(dp, animation));
Debug.Assert(IsPropertyAnimatable(d, dp));
Debug.Assert(HandoffBehaviorEnum.IsDefined(handoffBehavior),
"Public API caller of this internal method is responsible for validating that the HandoffBehavior value is valid.");
AnimationStorage storage = GetStorage(d, dp);
if (animation == null)
{
if (storage == null ||
handoffBehavior == HandoffBehavior.Compose)
{
// Composing with a null animation is a no-op.
return;
}
else
{
// When the incoming animation is passed in as null and
// handoffBehavior == HandoffBehavior.SnapshotAndReplace it means
// that we should stop any and all animation behavior for
// this property.
if (storage._hasStickySnapshotValue)
{
storage._hasStickySnapshotValue = false;
storage._animationClocks[0].CurrentStateInvalidated -= new EventHandler(storage.OnCurrentStateInvalidated);
}
storage._snapshotValue = DependencyProperty.UnsetValue;
storage.ClearAnimations();
}
}
else if (animation.BeginTime.HasValue)
{
// We have an animation
AnimationClock animationClock;
animationClock = animation.CreateClock(); // note that CreateClock also calls InternalBeginIn
ApplyAnimationClocks(d, dp, new AnimationClock[] { animationClock }, handoffBehavior);
// ApplyAnimationClocks has fixed up the storage and called
// WritePostscript already so we can just return.
return;
}
else if (storage == null)
{
// The user gave us an animation with a BeginTime of null which
// means snapshot the current value and throw away all animations
// for SnapshotAndReplace and means nothing for Compose.
// But since we don't have any animations the current we don't
// have to do anything for either of these cases.
return;
}
else if (handoffBehavior == HandoffBehavior.SnapshotAndReplace)
{
// This block handles the case where the user has called
// BeginAnimation with an animation that has a null begin time.
// We handle this by taking a snapshot value and throwing
// out the animation, which is the same as keeping it because
// we know it will never start.
//
// If the handoffBehavior is Compose, we ignore the user's call
// because it wouldn't mean anything unless they were planning
// on changing the BeginTime of their animation later, which we
// don't support.
// If _hasStickySnapshotValue is set, unset it and remove our
// event handler from the clock. The current snapshot value
// will still be used.
if (storage._hasStickySnapshotValue)
{
Debug.Assert(storage._animationClocks != null && storage._animationClocks.Count > 0,
"If _hasStickySnapshotValue is set we should have at least one animation clock stored in the AnimationStorage.");
storage._hasStickySnapshotValue = false;
storage._animationClocks[0].CurrentStateInvalidated -= new EventHandler(storage.OnCurrentStateInvalidated);
}
// Otherwise take a new snapshot value.
else
{
storage._snapshotValue = d.GetValue(dp);
}
storage.ClearAnimations();
}
// If storage were null we would have returned already.
storage.WritePostscript();
}
[FriendAccessAllowed] // Built into Core, also used by Framework.
internal static void ApplyAnimationClocks(
DependencyObject d,
DependencyProperty dp,
IList <AnimationClock> animationClocks,
HandoffBehavior handoffBehavior)
{
Debug.Assert(animationClocks != null,
"The animationClocks parameter should not be passed in as null.");
Debug.Assert(animationClocks.Count > 0,
"The animationClocks parameter should contain at least one clock.");
Debug.Assert(!animationClocks.Contains(null),
"The animationClocks parameter should not contain a null entry.");
Debug.Assert(HandoffBehaviorEnum.IsDefined(handoffBehavior),
"Public API caller of this internal method is responsible for validating that the HandoffBehavior value is valid.");
AnimationStorage storage = GetStorage(d, dp);
// handoffBehavior is SnapshotAndReplace or the situation is such
// that it is the equivalent because we have nothing to compose
// with.
if (handoffBehavior == HandoffBehavior.SnapshotAndReplace ||
storage == null ||
storage._animationClocks == null)
{
if (storage != null)
{
EventHandler handler = new EventHandler(storage.OnCurrentStateInvalidated);
// If we have a sticky snapshot value, the clock that would have
// unstuck it is being replaced, so we need to remove our event
// handler from that clock.
if (storage._hasStickySnapshotValue)
{
storage._animationClocks[0].CurrentStateInvalidated -= handler;
}
// Calculate a snapshot value if we don't already have one
// since the last tick.
else
{
storage._snapshotValue = d.GetValue(dp);
}
// If we have a new clock in a stopped state, then the snapshot
// value will be sticky.
if (animationClocks[0].CurrentState == ClockState.Stopped)
{
storage._hasStickySnapshotValue = true;
animationClocks[0].CurrentStateInvalidated += new EventHandler(storage.OnCurrentStateInvalidated);
}
// Otherwise it won't be sticky.
else
{
storage._hasStickySnapshotValue = false;
}
storage.ClearAnimations();
}
else
{
storage = CreateStorage(d, dp);
}
// Add and attach new animation.
storage._animationClocks = new FrugalObjectList <AnimationClock>(animationClocks.Count);
for (int i = 0; i < animationClocks.Count; i++)
{
Debug.Assert(animationClocks[i] != null);
storage._animationClocks.Add(animationClocks[i]);
storage.AttachAnimationClock(animationClocks[i], storage._removeRequestedHandler);
}
}
else
{
Debug.Assert(handoffBehavior == HandoffBehavior.Compose);
Debug.Assert(storage != null);
Debug.Assert(storage._animationClocks != null);
FrugalObjectList <AnimationClock> newClockCollection = new FrugalObjectList <AnimationClock>(storage._animationClocks.Count + animationClocks.Count);
for (int i = 0; i < storage._animationClocks.Count; i++)
{
newClockCollection.Add(storage._animationClocks[i]);
}
storage._animationClocks = newClockCollection;
for (int i = 0; i < animationClocks.Count; i++)
{
newClockCollection.Add(animationClocks[i]);
storage.AttachAnimationClock(animationClocks[i], storage._removeRequestedHandler);
}
}
storage.WritePostscript();
}