BackEase class

Represents an easing function that changes a value in the opposite direction of the main function during part of a duration, then reverses and finishes the function-over-time behavior in a conventional way.

Inheritance

Object

  DependencyObject

    EasingFunctionBase

      BackEase

Syntax

public sealed class BackEase : EasingFunctionBase

<BackEase .../>

Attributes

ActivatableAttribute(NTDDI_WIN8)

MarshalingBehaviorAttribute(Agile)

StaticAttribute(Windows.UI.Xaml.Media.Animation.IBackEaseStatics, NTDDI_WIN8)

ThreadingAttribute(Both)

VersionAttribute(NTDDI_WIN8)

WebHostHiddenAttribute()

Members

The BackEase class has these types of members:

• Constructors
• Methods
• Properties

Constructors

The BackEase class has these constructors.

Methods

The BackEase class has these methods. It also inherits methods from the Object class.

Properties

The BackEase class has these properties.

Remarks

BackEase is one of the two easing functions that can produce a value outside of the normal From/To range. (The other is ElasticEase.)

• If EasingMode is EaseIn (the default) then the function starts in a typical way, but near the end will exceed the To value and then come back to the To value at the end.
• If EasingMode is EaseOut then the function starts by changing the value in the opposite direction of the value change that From and To indicate, in other words it initially produces a value that's less than the From value.
• If EasingMode is EaseInOut then the function gives values that are less than From at the beginning and greater than To near the end.

This illustration shows a function-over-time graph approximation for a BackEase for each of the three possible EasingMode values, with Amplitude as its default value.

The Oscillations property declares how many times the function oscillates and crosses into values that are actually below the starting From value.

You might get best results by just experimenting with the Springiness, Oscillations and EasingMode properties until the animation is visually doing what you want for your animated property value scenario.

An easing function can be applied to the EasingFunction properties of From/To/By animations, or to the EasingFunction properties of key-frame types used for the Easing variants of key-frame animations. For more info, see Key-frame animations and easing function animations.

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.

<StackPanel x:Name="LayoutRoot" >
    <StackPanel.Resources>
        <Storyboard x:Name="myStoryboard">
                <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>
        </Storyboard>
    </StackPanel.Resources>

    <Rectangle Margin="60" x:Name="myRectangle" PointerPressed="Pointer_Clicked" 
     Fill="Blue" Width="50" Height="50" >
        
        <Rectangle.RenderTransform>
            <ScaleTransform x:Name="myScaleTransform" />
        </Rectangle.RenderTransform>
        
    </Rectangle>
</StackPanel>

// When the user clicks the rectangle, the animation
// begins. 
private void Pointer_Clicked(object sender, PointerRoutedEventArgs e)
{
    myStoryboard.Begin();
}

Requirements

See also

Storyboarded animations

PowerEase

BounceEase

CircleEase

CubicEase

ElasticEase

ExponentialEase

QuadraticEase

QuarticEase

QuinticEase

SineEase

Build date: 12/4/2012