BackEase Class

Reference

Definition

Namespace:: System.Windows.Media.Animation

Assembly:: PresentationCore.dll

Important

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Represents an easing function that retracts the motion of an animation slightly before it begins to animate in the path indicated.

public ref class BackEase : System::Windows::Media::Animation::EasingFunctionBase

public class BackEase : System.Windows.Media.Animation.EasingFunctionBase

type BackEase = class
    inherit EasingFunctionBase

Public Class BackEase
Inherits EasingFunctionBase

Inheritance: Object

DispatcherObject

DependencyObject

Freezable

EasingFunctionBase
BackEase

Examples

The following example applies a BackEase easing function to a DoubleAnimation to create an animation that retracts slightly at the beginning and end of the animation.

<Rectangle Name="MyRectangle" Margin="60" Width="50" Height="50" Fill="Blue">
      <Rectangle.Triggers>
          <EventTrigger RoutedEvent="Rectangle.MouseDown">
              <BeginStoryboard>
                  <Storyboard>
                      <DoubleAnimation From="1" To="2" Duration="00:00:1" 
                     Storyboard.TargetName="myScaleTransform" 
                     Storyboard.TargetProperty="ScaleX">
                          <DoubleAnimation.EasingFunction>
                              <BackEase Amplitude="0.3" EasingMode="EaseInOut" />
                          </DoubleAnimation.EasingFunction>
                      </DoubleAnimation>
                      <DoubleAnimation From="1" To="2" Duration="00:00:1" 
                     Storyboard.TargetName="myScaleTransform" 
                     Storyboard.TargetProperty="ScaleY">
                          <DoubleAnimation.EasingFunction>
                              <BackEase Amplitude="0.3" EasingMode="EaseInOut" />
                          </DoubleAnimation.EasingFunction>
                      </DoubleAnimation>

                  </Storyboard>
              </BeginStoryboard>
          </EventTrigger>
      </Rectangle.Triggers>
      <Rectangle.RenderTransform>
          <ScaleTransform x:Name="myScaleTransform" />
      </Rectangle.RenderTransform>

  </Rectangle>

Remarks

You can control when the "back up" behavior occurs in an animation by specifying the EasingMode property value on an animation. The following graph demonstrate the different values of EasingMode, where f(t) represents the animation progress and t represents time.

BackEase EasingMode graphs.

The formula used for this function is the following.

BackEase formula.

Note

Because this animation causes values to retract before progressing, the animation might interpolate into negative numbers unexpectedly. This can cause errors when animating properties that do not allow negative numbers. For example, if you apply this animation to the Height of an object (e.g. from 0 to 200 with an EasingMode of EaseIn), the animation will attempt to interpolate through negative numbers for Height which will throw an error.

There are several other easing functions besides BackEase. In addition to using the easing functions included in the run-time, you can create your own custom easing functions by inheriting from EasingFunctionBase.

XAML Object Element Usage

<BackEase .../>

Constructors

BackEase()

Initializes a new instance of the BackEase class.

Fields

AmplitudeProperty

Identifies the Amplitude dependency property.

Properties

Amplitude	Gets or sets the amplitude of retraction associated with a BackEase animation.
CanFreeze	Gets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable)
DependencyObjectType	Gets the DependencyObjectType that wraps the CLR type of this instance. (Inherited from DependencyObject)
Dispatcher	Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject)
EasingMode	Gets or sets a value that specifies how the animation interpolates. (Inherited from EasingFunctionBase)
IsFrozen	Gets a value that indicates whether the object is currently modifiable. (Inherited from Freezable)
IsSealed	Gets a value that indicates whether this instance is currently sealed (read-only). (Inherited from DependencyObject)

Methods

CheckAccess()	Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject)
ClearValue(DependencyProperty)	Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier. (Inherited from DependencyObject)
ClearValue(DependencyPropertyKey)	Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey. (Inherited from DependencyObject)
Clone()	Creates a modifiable clone of the Freezable, making deep copies of the object's values. When copying the object's dependency properties, this method copies expressions (which might no longer resolve) but not animations or their current values. (Inherited from Freezable)
CloneCore(Freezable)	Makes the instance a clone (deep copy) of the specified Freezable using base (non-animated) property values. (Inherited from Freezable)
CloneCurrentValue()	Creates a modifiable clone (deep copy) of the Freezable using its current values. (Inherited from Freezable)
CloneCurrentValueCore(Freezable)	Makes the instance a modifiable clone (deep copy) of the specified Freezable using current property values. (Inherited from Freezable)
CoerceValue(DependencyProperty)	Coerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject. (Inherited from DependencyObject)
CreateInstance()	Initializes a new instance of the Freezable class. (Inherited from Freezable)
CreateInstanceCore()	Creates a new instance of the Freezable derived class. When creating a derived class, you must override this method.
Ease(Double)	Transforms normalized time to control the pace of an animation. (Inherited from EasingFunctionBase)
EaseInCore(Double)	Provides the logic portion of the easing function that you can override to produce the EaseIn mode of the custom easing function.
Equals(Object)	Determines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject)
Freeze()	Makes the current object unmodifiable and sets its IsFrozen property to `true`. (Inherited from Freezable)
FreezeCore(Boolean)	Makes the Freezable object unmodifiable or tests whether it can be made unmodifiable. (Inherited from Freezable)
GetAsFrozen()	Creates a frozen copy of the Freezable, using base (non-animated) property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetAsFrozenCore(Freezable)	Makes the instance a frozen clone of the specified Freezable using base (non-animated) property values. (Inherited from Freezable)
GetCurrentValueAsFrozen()	Creates a frozen copy of the Freezable using current property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable)
GetCurrentValueAsFrozenCore(Freezable)	Makes the current instance a frozen clone of the specified Freezable. If the object has animated dependency properties, their current animated values are copied. (Inherited from Freezable)
GetHashCode()	Gets a hash code for this DependencyObject. (Inherited from DependencyObject)
GetLocalValueEnumerator()	Creates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject. (Inherited from DependencyObject)
GetType()	Gets the Type of the current instance. (Inherited from Object)
GetValue(DependencyProperty)	Returns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject)
InvalidateProperty(DependencyProperty)	Re-evaluates the effective value for the specified dependency property. (Inherited from DependencyObject)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnChanged()	Called when the current Freezable object is modified. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject, DependencyProperty)	This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code. (Inherited from Freezable)
OnFreezablePropertyChanged(DependencyObject, DependencyObject)	Ensures that appropriate context pointers are established for a DependencyObjectType data member that has just been set. (Inherited from Freezable)
OnPropertyChanged(DependencyPropertyChangedEventArgs)	Overrides the DependencyObject implementation of OnPropertyChanged(DependencyPropertyChangedEventArgs) to also invoke any Changed handlers in response to a changing dependency property of type Freezable. (Inherited from Freezable)
ReadLocalValue(DependencyProperty)	Returns the local value of a dependency property, if it exists. (Inherited from DependencyObject)
ReadPreamble()	Ensures that the Freezable is being accessed from a valid thread. Inheritors of Freezable must call this method at the beginning of any API that reads data members that are not dependency properties. (Inherited from Freezable)
SetCurrentValue(DependencyProperty, Object)	Sets the value of a dependency property without changing its value source. (Inherited from DependencyObject)
SetValue(DependencyProperty, Object)	Sets the local value of a dependency property, specified by its dependency property identifier. (Inherited from DependencyObject)
SetValue(DependencyPropertyKey, Object)	Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property. (Inherited from DependencyObject)
ShouldSerializeProperty(DependencyProperty)	Returns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject)
ToString()	Returns a string that represents the current object. (Inherited from Object)
VerifyAccess()	Enforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject)
WritePostscript()	Raises the Changed event for the Freezable and invokes its OnChanged() method. Classes that derive from Freezable should call this method at the end of any API that modifies class members that are not stored as dependency properties. (Inherited from Freezable)
WritePreamble()	Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the beginning of any API that writes to data members that are not dependency properties. (Inherited from Freezable)

Events

Changed

Occurs when the Freezable or an object it contains is modified.

(Inherited from Freezable)

Applies to

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