/// <summary>
/// Arranges the <see cref="UIElement"/> for hte specified <see cref="Rect"/>
/// bounds.
/// </summary>
/// <param name="element">
/// The <see cref="UIElement"/> to arrange.
/// </param>
/// <param name="bounds">
/// The <see cref="Rect"/> bound for the element.
/// </param>
protected void ArrangeElement(UIElement element, Rect bounds)
{
if (element == null)
{
return;
}
if (!renderingListener.IsListening)
{
renderingListener.StartListening();
}
ItemAnimationData animationData = GetAnimationData(element);
if (animationData == null)
{
animationData = new ItemAnimationData();
SetAnimationData(element, animationData);
element.RenderTransform = animationData.Transform;
animationData.Current = OnElementAdded(element, bounds);
}
animationData.Target = bounds.Location;
element.Arrange(bounds);
}
private void OnRendering(object sender, EventArgs eventArgs)
{
double dampening = Dampening;
double attractionFactor = Attraction * .01;
double variation = Variation;
bool hasChanges = false;
for (int i = 0; i < InternalChildren.Count; i++)
{
ItemAnimationData animationData = GetAnimationData(Children[i]);
if (animationData != null)
{
attractionFactor *= 1 + (variation * animationData.RandomSeed - .5);
Vector currentVelocity = animationData.LocationVelocity;
Point newLocation;
Vector newVelocity;
Vector diff = animationData.Offset;
if (diff.Length > MinimumValueDelta || currentVelocity.Length > MinimumValueDelta)
{
newVelocity = currentVelocity * (1 - dampening);
newVelocity += diff * attractionFactor;
if (currentVelocity.Length > TerminalVelocity)
{
newVelocity *= TerminalVelocity / currentVelocity.Length;
}
newLocation = animationData.Current + newVelocity;
hasChanges = true;
}
else
{
newLocation = animationData.Target;
newVelocity = new Vector();
}
animationData.Current = newLocation;
animationData.LocationVelocity = newVelocity;
Vector transformVector = animationData.Current - animationData.Target;
animationData.Transform.X = transformVector.X;
animationData.Transform.Y = transformVector.Y;
}
}
// Stop listening if no changes for all elements
if (!hasChanges)
{
renderingListener.StopListening();
}
}
private static void SetAnimationData(DependencyObject element, ItemAnimationData value)
{
if (element == null)
{
throw new ArgumentNullException("element");
}
if (value == null)
{
throw new ArgumentNullException("value");
}
element.SetValue(AnimationDataProperty, value);
}
/// <summary>
/// Invoked when the System.Windows.Media.VisualCollection of a visual object
/// is modified.
/// </summary>
/// <param name="visualAdded">
/// The System.Windows.Media.Visual that was added to the collection.
/// </param>
/// <param name="visualRemoved">
/// The System.Windows.Media.Visual that was removed from the collection.
/// </param>
protected override void OnVisualChildrenChanged(DependencyObject visualAdded, DependencyObject visualRemoved)
{
if (visualRemoved == null)
{
return;
}
ItemAnimationData animationData = GetAnimationData(visualRemoved);
if (animationData == null)
{
return;
}
visualRemoved.ClearValue(AnimationDataProperty);
}
