InteractionTrackerInertiaRestingValue Class

Definition

Namespace:

Windows.UI.Composition.Interactions

An ExpressionAnimation that defines the rest position after an interaction.

The InteractionTrackerInertiaRestingValue class defines two ExpressionAnimations that calculate an explicit resting position for InteractionTracker when a particular condition is met. The InteractionTrackerInertiaRestingValue is defined as two parts: The conditional statement in which the InteractionTracker ’s specific resting location needs to be explicitly defined if true and the equation that describes a mathematical relationship that outputs the location. Utilize the InteractionTrackerInertiaRestingValue class when needing to ensure InteractionTracker lands on a specific location after an interaction occurs.

public ref class InteractionTrackerInertiaRestingValue sealed : InteractionTrackerInertiaModifier

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 196608)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class InteractionTrackerInertiaRestingValue final : InteractionTrackerInertiaModifier

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 196608)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class InteractionTrackerInertiaRestingValue : InteractionTrackerInertiaModifier

Public NotInheritable Class InteractionTrackerInertiaRestingValue
Inherits InteractionTrackerInertiaModifier

Inheritance

Object Platform::Object IInspectable CompositionObject InteractionTrackerInertiaModifier InteractionTrackerInertiaRestingValue

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Windows requirements

Device family	Windows 10 Anniversary Edition (introduced in 10.0.14393.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v3.0)

Examples

void MandatorySingleSnapPoints(ContainerVisual containerVisual, Visual contentVisual)
{
  //
  // Set up our inertia modifiers to behave as dmanip's "single mandatory" snap-points, at a
  // regular interval of 50px.
  //

  const float snapPointRange = 50.0f;

  //
  // Configure a "snap-point" to handle upward direction (to previous item).
  //

  var modifier1 = InteractionTrackerInertiaRestingValue.Create(_compositor);

  // Add a condition for when this upward “snap-point” applies.
  modifier1.Condition = _compositor.CreateExpressionAnimation(
    "this.Target.NaturalRestingPosition.y < " + 
    "(this.StartingValue - mod(this.StartingValue, snapPointRange) + snapPointRange / 2)");

  modifier1.Condition.SetScalarParameter("snapPointRange", snapPointRange);

  // Configure the resting spot when the condition is met 
  modifier1.EndPoint = _compositor.CreateExpressionAnimation(
    "this.StartingValue - mod(this.StartingValue, snapPointRange)");

  modifier1.EndPoint.SetScalarParameter("snapPointRange", snapPointRange);

  //
  // Configure a "snap-point" to handle downward direction (to next item).
  //

  var modifier2 = InteractionTrackerInertiaRestingValue.Create(_compositor);

  // Add a condition for when this downward “snap-point” applies.
  modifier2.Condition = _compositor.CreateExpressionAnimation(
    "this.Target.NaturalRestingPosition.y >= " + 
    "(this.StartingValue - mod(this.StartingValue, snapPointRange) + snapPointRange / 2)");

  modifier2.Condition.SetScalarParameter("snapPointRange", snapPointRange);

  // Configure the resting spot when the condition is met.
  modifier2.EndPoint = _compositor.CreateExpressionAnimation(
    "this.StartingValue + snapPointRange - mod(this.StartingValue, snapPointRange)");

  modifier2.EndPoint.SetScalarParameter("snapPointRange", snapPointRange);

  var modifiers = new InteractionTrackerInertiaRestingValue[] { modifier1, modifier2 };

  //
  // Add our "snap-point" inertia modifiers to the Y position of the InteractionTracker.
  //

  _tracker.ConfigurePositionYInertiaModifiers(modifiers);
}

Remarks

When attaching the InteractionTrackerInertiaRestingValue modifier to the InteractionTracker, you configure it to either the X/Y Position or Scale.

The ExpressionAnimation defining the condition property only gets run once, when the interaction completes (finger released), while the RestingValue Expression gets run every frame.

InteractionTrackerInertiaRestingValue modifiers explicitly defines the resting position of InteractionTracker when the condition is met. It does not however define the motion to this explicit location – the system will handle that. Thus, if you need InteractionTracker to take a particular motion, but do not require it to land at an exact spot, utilize the InteractionTrackerInertiaMotion modifier.

Properties

Comment	A string to associate with the CompositionObject. (Inherited from CompositionObject)
Compositor	The Compositor used to create this CompositionObject. (Inherited from CompositionObject)
Condition	An ExpressionAnimation describing when the modifier should be applied. The Condition property is an ExpressionAnimation that defines when the InteractionTracker should have a specific resting position. This expression gets run once after the interaction occurs and must resolve to a type Bool, otherwise an error will be thrown when the condition is evaluated. See the ExpressionAnimation class page for more details on building expressions.
Dispatcher	The dispatcher for the CompositionObject. (Inherited from CompositionObject)
DispatcherQueue	Gets the DispatcherQueue for the CompostionObject. (Inherited from CompositionObject)
ImplicitAnimations	The collection of implicit animations attached to this object. (Inherited from CompositionObject)
Properties	The collection of properties associated with the CompositionObject. (Inherited from CompositionObject)
RestingValue	An ExpressionAnimation to define the resting value of InteractionTracker if the expression in the Condition property is true. The Resting property is an ExpressionAnimation that describes where InteractionTracker will move to after an interaction if it’s corresponding condition is met. This expression will be run every frame while InteractionTracker is in Inertia and must resolve to a type Float, otherwise an error will be thrown when the equation is evaluated. See the ExpressionAnimation class page for more details on building expressions.

Methods

Close()	Closes the CompositionObject and releases system resources. (Inherited from CompositionObject)
ConnectAnimation(String, CompositionAnimation)	Connects and animation. (Inherited from CompositionObject)
Create(Compositor)	Creates an instance of InteractionTrackerInertiaRestingValue.
DisconnectAnimation(String)	Disconnects an animation. (Inherited from CompositionObject)
Dispose()	Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources. (Inherited from CompositionObject)
PopulatePropertyInfo(String, AnimationPropertyInfo)	Defines a property that can be animated. (Inherited from CompositionObject)
StartAnimation(String, CompositionAnimation)	Connects an animation with the specified property of the object and starts the animation. (Inherited from CompositionObject)
StartAnimation(String, CompositionAnimation, AnimationController)	Connects an animation with the specified property of the object and starts the animation. (Inherited from CompositionObject)
StartAnimationGroup(ICompositionAnimationBase)	Starts an animation group. The StartAnimationGroup method on CompositionObject lets you start CompositionAnimationGroup. All the animations in the group will be started at the same time on the object. (Inherited from CompositionObject)
StopAnimation(String)	Disconnects an animation from the specified property and stops the animation. (Inherited from CompositionObject)
StopAnimationGroup(ICompositionAnimationBase)	Stops an animation group. (Inherited from CompositionObject)
TryGetAnimationController(String)	Returns an AnimationController for the animation running on the specified property. (Inherited from CompositionObject)

See also

• InteractionTrackerInertiaModifier
• IClosable