SplineDoubleKeyFrame Class

May 11, 2014

Animates from the Double value of the previous key frame to its own Value using splined interpolation.

System.Object
  System.Windows.DependencyObject
    System.Windows.Media.Animation.DoubleKeyFrame
      System.Windows.Media.Animation.SplineDoubleKeyFrame

Namespace:  System.Windows.Media.Animation
Assembly:  System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.

'Declaration
Public NotInheritable Class SplineDoubleKeyFrame _
	Inherits DoubleKeyFrame
<SplineDoubleKeyFrame .../>

The SplineDoubleKeyFrame type exposes the following members.

  NameDescription
Public methodSplineDoubleKeyFrameInitializes a new instance of the SplineDoubleKeyFrame class.
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  NameDescription
Public propertyDispatcherGets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
Public propertyKeySplineGets or sets the two control points that define animation progress for this key frame.
Public propertyKeyTimeGets or sets the time at which the key frame's target Value should be reached. (Inherited from DoubleKeyFrame.)
Public propertyValueGets or sets the key frame's target value. (Inherited from DoubleKeyFrame.)
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  NameDescription
Public methodCheckAccessDetermines whether the calling thread has access to this object. (Inherited from DependencyObject.)
Public methodClearValueClears the local value of a dependency property. (Inherited from DependencyObject.)
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetAnimationBaseValueReturns any base value established for a Windows Phone dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetValueReturns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodReadLocalValueReturns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)
Public methodSetValueSets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public fieldStatic memberKeySplinePropertyIdentifies the KeySpline dependency property.
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This class is used as part of a DoubleKeyFrameCollection in conjunction with a DoubleAnimationUsingKeyFrames to animate a Double property value along a set of key frames.

A key frame defines a segment of the DoubleAnimationUsingKeyFrames to which it belongs. Each key frame has a target Value and a KeyTime. The KeyTime specifies the time at which the key frame's Value should be reached. A key frame animates from the target value of the previous key frame to its own target value. It starts when the previous key frame ends and ends when its own key time is reached.

Spline key frames like SplineDoubleKeyFrame create a variable transition between values that is determined by the KeySpline property. Splined interpolation can be used to achieve more realistic "real world" timing effects such as acceleration and deceleration.

A cubic Bezier curve is defined by a start point, an end point, and two control points. The KeySpline property of a spline key frame defines the two control points of a Bezier curve that extends from (0,0) to (1,1). The first control point controls the curve factor of the first half of the Bezier curve, and the second control point controls the curve factor of the second half of the Bezier segment. The resulting curve describes the rate of change for that spline key frame. The steeper the curve, the faster the key frame changes its values. As the curve gets flatter, the key frame changes its values more slowly.

The following example moves a rectangle across a screen. The example uses the DoubleAnimationUsingKeyFrames class to animate the X property of a TranslateTransform applied to a Rectangle. This animation uses three key frames in the following manner:

  1. During the first three seconds, it uses an instance of the LinearDoubleKeyFrame class to move the rectangle along a path at a steady rate from its starting position to the 500 position. Linear key frames like LinearDoubleKeyFrame create a smooth linear transition between values.

  2. At the end of the fourth second, it uses an instance of the DiscreteDoubleKeyFrame class to suddenly move the rectangle to the next position. Discrete key frames like DiscreteDoubleKeyFrame create sudden jumps between values. In this example, the rectangle is at the starting position and then suddenly appears at the 500 position.

  3. In the final two seconds, it uses an instance of the SplineDoubleKeyFrame class to move the rectangle back to its starting position. Spline key frames such as SplineDoubleKeyFrame create a variable transition between values according to the value of the KeySpline property. In this example, the rectangle begins by moving slowly and then speeds up exponentially toward the end of the time segment.


' Start the animation when the object loads
Private Sub Start_Animation(ByVal sender As Object, ByVal e As EventArgs)
    myStoryboard.Begin()
End Sub



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

            <!-- Animate the TranslateTransform's X property
             from 0 to 350, then 50,
             then 200 over 10 seconds. -->
            <DoubleAnimationUsingKeyFrames
          Storyboard.TargetName="MyAnimatedTranslateTransform"
          Storyboard.TargetProperty="X"
          Duration="0:0:10">

                <!-- Using a LinearDoubleKeyFrame, the rectangle moves 
                 steadily from its starting position to 500 over 
                 the first 3 seconds.  -->
                <LinearDoubleKeyFrame Value="500" KeyTime="0:0:3" />

                <!-- Using a DiscreteDoubleKeyFrame, the rectangle suddenly 
                 appears at 400 after the fourth second of the animation. -->
                <DiscreteDoubleKeyFrame Value="400" KeyTime="0:0:4" />

                <!-- Using a SplineDoubleKeyFrame, the rectangle moves 
                 back to its starting point. The
                 animation starts out slowly at first and then speeds up. 
                 This KeyFrame ends after the 6th
                 second. -->
                <SplineDoubleKeyFrame KeySpline="0.6,0.0 0.9,0.00" Value="0" KeyTime="0:0:6" />

            </DoubleAnimationUsingKeyFrames>
        </Storyboard>
    </StackPanel.Resources>
    <Rectangle Fill="Blue" Width="50" Height="50" Loaded="Start_Animation">
        <Rectangle.RenderTransform>
            <TranslateTransform x:Name="MyAnimatedTranslateTransform" 
             X="0" Y="0" />
        </Rectangle.RenderTransform>
    </Rectangle>
</StackPanel>


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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