KeySpline Class
This class is used by a spline key frame to define animation progress.
System.Windows.Threading::DispatcherObject
System.Windows::DependencyObject
System.Windows::Freezable
System.Windows.Media.Animation::KeySpline
Assembly: PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
[TypeConverterAttribute(typeof(KeySplineConverter))] [LocalizabilityAttribute(LocalizationCategory::None, Readability = Readability::Unreadable)] public ref class KeySpline : public Freezable, IFormattable
<KeySpline .../>
<object property="cp1X,cp1Y cp2X,cp2Y"/>
XAML Values
The separator between values may be either comma or one or more spaces. The convention shown here of commas between components of a point and space between points is a recommended convention. Do not use a comma as the decimal point within the values of point components, even if that is the norm in your culture. XAML values are treated as en-us in all type conversion cases, and the comma is thus interpreted as the separator and not as the intended decimal point.
The KeySpline type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | KeySpline() | Initializes a new instance of the KeySpline class. |
![]() | KeySpline(Point, Point) | Initializes a new instance of the KeySpline class with the specified control points. |
![]() | KeySpline(Double, Double, Double, Double) | Initializes a new instance of the KeySpline class with the specified coordinates for the control points. |
| Name | Description | |
|---|---|---|
![]() | CanFreeze | Gets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable.) |
![]() | ControlPoint1 | The first control point used to define a Bezier curve that describes a KeySpline. |
![]() | ControlPoint2 | The second control point used to define a Bezier curve that describes a KeySpline. |
![]() | 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.) |
![]() | 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.) |
| Name | Description | |
|---|---|---|
![]() | 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 | Makes this instance a deep copy of the specified KeySpline. When copying dependency properties, this method copies resource references and data bindings (but they might no longer resolve) but not animations or their current values. (Overrides Freezable::CloneCore(Freezable).) |
![]() | CloneCurrentValue | Creates a modifiable clone (deep copy) of the Freezable using its current values. (Inherited from Freezable.) |
![]() | CloneCurrentValueCore | Makes this instance a modifiable deep copy of the specified KeySpline using current property values. Resource references, data bindings, and animations are not copied, but their current values are. (Overrides Freezable::CloneCurrentValueCore(Freezable).) |
![]() | CoerceValue | 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 KeySpline. (Overrides Freezable::CreateInstanceCore().) |
![]() | Equals | Determines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | Freeze() | Makes the current object unmodifiable and sets its IsFrozen property to true. (Inherited from Freezable.) |
![]() | FreezeCore | 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 | Makes this instance a clone of the specified KeySpline object. (Overrides Freezable::GetAsFrozenCore(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 | Makes this instance a frozen clone of the specified KeySpline. Resource references, data bindings, and animations are not copied, but their current values are. (Overrides Freezable::GetCurrentValueAsFrozenCore(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.) |
![]() | GetSplineProgress | Calculates spline progress from a supplied linear progress. |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | GetValue | Returns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject.) |
![]() | InvalidateProperty | 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 KeySpline object is modified. (Overrides Freezable::OnChanged().) |
![]() | OnFreezablePropertyChanged(DependencyObject, DependencyObject) | Ensures that appropriate context pointers are established for a DependencyObjectType data member that has just been set. (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.) |
![]() | OnPropertyChanged | Overrides the DependencyObject implementation of OnPropertyChanged to also invoke any Changed handlers in response to a changing dependency property of type Freezable. (Inherited from Freezable.) |
![]() | ReadLocalValue | 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 | 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 | Returns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject.) |
![]() | ToString() | Creates a string representation of this instance of KeySpline based on the current culture. (Overrides Object::ToString().) |
![]() | ToString(IFormatProvider) | Creates a string representation of this KeySpline based on the supplied IFormatProvider. |
![]() | 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.) |
| Name | Description | |
|---|---|---|
![]() ![]() | IFormattable::ToString | Formats the value of the current instance using the specified format. |
To understand how a KeySpline works, it is helpful to understand cubic Bezier curves. A cubic Bezier curve is defined by a start point, an end point, and two control points. The two coordinates in the KeySpline defines those two control points. When describing key splines, the start point of the Bezier curve is always 0, and the end point is always 1, which is why you define only the two control points. The resulting curve specifies how an animation is interpolated during a time segment; that is, the curve represents the rate of change in the animation's target attribute over the time segment. To better see the relationship between animation progress and a Bezier curve, see Key Spline Animation Sample.
This example shows how to animate the value of a property that takes a Double by using key frames.
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, which repeats indefinitely, uses three key frames in the following manner:
During the first three seconds, 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.
At the end of the fourth second, 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.
In the final two seconds, uses an instance of the SplineDoubleKeyFrame class to move the rectangle back to its starting position. Spline key frames like 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.
<!-- This example shows how to use the DoubleAnimationUsingKeyFrames to animate the position of an object. Key frame animations enable you to create complex animations by specifying multiple destination values and controlling the animation's interpolation method. --> <Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="DoubleAnimationUsingKeyFrames Example" Background="White" Margin="20"> <Canvas Width="610" Height="300"> <!-- The position of this rectangle is animated using a key frame animation. --> <Rectangle Canvas.Top="100" Canvas.Left="10" Height="100" Width="100" Stroke="Black" StrokeThickness="5"> <Rectangle.RenderTransform> <TranslateTransform x:Name="AnimatedTranslateTransform" /> </Rectangle.RenderTransform> <Rectangle.Triggers> <EventTrigger RoutedEvent="Rectangle.Loaded"> <BeginStoryboard> <Storyboard> <!-- Animate the TranslateTransform.X property using 3 KeyFrames which animates the rectangle along a straight line. This animation repeats indefinitely. --> <DoubleAnimationUsingKeyFrames Storyboard.TargetName="AnimatedTranslateTransform" Storyboard.TargetProperty="X" Duration="0:0:6" RepeatBehavior="Forever"> <!-- 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> </BeginStoryboard> </EventTrigger> </Rectangle.Triggers> </Rectangle> </Canvas> </Page>
For the complete sample, see KeyFrame Animation Sample.
For consistency with other animation examples, the code versions of this example use a Storyboard object to apply the DoubleAnimationUsingKeyFrames. Alternatively, when applying a single animation in code, it is simpler to use the BeginAnimation method instead of using a Storyboard. For an example, see How to: Animate a Property Without Using a Storyboard.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
