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Cómo animar un objeto a lo largo de una trayectoria (animación de matriz con acumulación de offset)

En este ejemplo se muestra cómo usar la clase MatrixAnimationUsingPath para animar un objeto a lo largo de una trayectoria y hacer que esa animación acumule sus valores de desplazamiento a medida que se repite.

Ejemplo

En el ejemplo siguiente se usa el objeto MatrixAnimationUsingPath para animar la propiedad Matrix de un MatrixTransform aplicado a un botón. Como resultado, un botón se mueve a lo largo de un trazado curvado.

Además, el ejemplo establece la propiedad IsOffsetCumulative en true, lo que hace que el desplazamiento de la matriz animada se acumule a medida que se repite la animación. Dado que el desplazamiento se acumula, el botón se mueve más lejos a través de la pantalla cuando se repite la animación, en lugar de restablecer la posición inicial.

<Page 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Margin="20"
  xmlns:PresentationOptions="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options" 
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  mc:Ignorable="PresentationOptions">
  
  <Canvas Width="400" Height="400">
  

    <!-- The Button that is animated across the screen by animating
         the MatrixTransform applied to the button. -->
    <Button MinWidth="100" Content="A Button">
      <Button.RenderTransform>
        <MatrixTransform x:Name="myMatrixTransform">
          <MatrixTransform.Matrix >
            <Matrix />
          </MatrixTransform.Matrix>
        </MatrixTransform>
      </Button.RenderTransform>
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard>
              <MatrixAnimationUsingPath
              Storyboard.TargetName="myMatrixTransform"
              Storyboard.TargetProperty="Matrix"
              IsOffsetCumulative="True"
              Duration="0:0:5" 
              RepeatBehavior="2x">
                <MatrixAnimationUsingPath.PathGeometry>
                  <PathGeometry 
                    Figures="M 10,100 C 35,0 135,0 160,100 180,190 285,200 310,100" 
                    PresentationOptions:Freeze="True" />
                </MatrixAnimationUsingPath.PathGeometry>
              </MatrixAnimationUsingPath>
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Button.Triggers>
      
    </Button>   
  </Canvas>
</Page>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace SDKSample
{

    /// <summary>
    /// Shows how to use the MatrixAnimationUsingPath.IsOffsetCumulative
    /// property to make a MatrixAnimatioinUsingPath accumulate
    /// its values when it repeats.
    /// </summary>
    public class MatrixAnimationUsingPathExampleOffsetCumulative : Page
    {

        public MatrixAnimationUsingPathExampleOffsetCumulative()
        {
            this.Margin = new Thickness(20);

            // Create a NameScope for the page so that
            // we can use Storyboards.
            NameScope.SetNameScope(this, new NameScope());

            // Create a button.
            Button aButton = new Button();
            aButton.MinWidth = 100;
            aButton.Content = "A Button";

            // Create a MatrixTransform. This transform
            // will be used to move the button.
            MatrixTransform buttonMatrixTransform = new MatrixTransform();
            aButton.RenderTransform = buttonMatrixTransform;

            // Register the transform's name with the page
            // so that it can be targeted by a Storyboard.
            this.RegisterName("ButtonMatrixTransform", buttonMatrixTransform);

            // Create a Canvas to contain the button
            // and add it to the page.
            // Although this example uses a Canvas,
            // any type of panel will work.
            Canvas mainPanel = new Canvas();
            mainPanel.Width = 400;
            mainPanel.Height = 400;
            mainPanel.Children.Add(aButton);
            this.Content = mainPanel;

            // Create the animation path.
            PathGeometry animationPath = new PathGeometry();
            PathFigure pFigure = new PathFigure();
            pFigure.StartPoint = new Point(10, 100);
            PolyBezierSegment pBezierSegment = new PolyBezierSegment();
            pBezierSegment.Points.Add(new Point(35, 0));
            pBezierSegment.Points.Add(new Point(135, 0));
            pBezierSegment.Points.Add(new Point(160, 100));
            pBezierSegment.Points.Add(new Point(180, 190));
            pBezierSegment.Points.Add(new Point(285, 200));
            pBezierSegment.Points.Add(new Point(310, 100));
            pFigure.Segments.Add(pBezierSegment);
            animationPath.Figures.Add(pFigure);

            // Freeze the PathGeometry for performance benefits.
            animationPath.Freeze();

            // Create a MatrixAnimationUsingPath to move the
            // button along the path by animating
            // its MatrixTransform.
            MatrixAnimationUsingPath matrixAnimation =
                new MatrixAnimationUsingPath();
            matrixAnimation.PathGeometry = animationPath;

            // Set IsOffsetCumulative to true so that the animation
            // values accumulate when its repeats.
            matrixAnimation.IsOffsetCumulative = true;
            matrixAnimation.Duration = TimeSpan.FromSeconds(5);
            matrixAnimation.RepeatBehavior = new RepeatBehavior(2);

            // Set the animation to target the Matrix property
            // of the MatrixTransform named "ButtonMatrixTransform".
            Storyboard.SetTargetName(matrixAnimation, "ButtonMatrixTransform");
            Storyboard.SetTargetProperty(matrixAnimation,
                new PropertyPath(MatrixTransform.MatrixProperty));

            // Create a Storyboard to contain and apply the animation.
            Storyboard pathAnimationStoryboard = new Storyboard();
            pathAnimationStoryboard.Children.Add(matrixAnimation);

            // Start the animation when the button is clicked.
            aButton.Click += delegate(object sender, RoutedEventArgs e)
            {
                // Start the storyboard.
                pathAnimationStoryboard.Begin(this);
            };
        }
    }
}


Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports System.Windows.Navigation
Imports System.Windows.Shapes


Namespace SDKSample

    ''' <summary>
    ''' Shows how to use the MatrixAnimationUsingPath.IsOffsetCumulative
    ''' property to make a MatrixAnimatioinUsingPath accumulate
    ''' its values when it repeats.
    ''' </summary>
    Public Class MatrixAnimationUsingPathExampleOffsetCumulative
        Inherits Page

        Public Sub New()
            Me.Margin = New Thickness(20)

            ' Create a NameScope for the page so that
            ' we can use Storyboards.
            NameScope.SetNameScope(Me, New NameScope())

            ' Create a button.
            Dim aButton As New Button()
            aButton.MinWidth = 100
            aButton.Content = "A Button"

            ' Create a MatrixTransform. This transform
            ' will be used to move the button.
            Dim buttonMatrixTransform As New MatrixTransform()
            aButton.RenderTransform = buttonMatrixTransform

            ' Register the transform's name with the page
            ' so that it can be targeted by a Storyboard.
            Me.RegisterName("ButtonMatrixTransform", buttonMatrixTransform)

            ' Create a Canvas to contain the button
            ' and add it to the page.
            ' Although this example uses a Canvas,
            ' any type of panel will work.
            Dim mainPanel As New Canvas()
            mainPanel.Width = 400
            mainPanel.Height = 400
            mainPanel.Children.Add(aButton)
            Me.Content = mainPanel

            ' Create the animation path.
            Dim animationPath As New PathGeometry()
            Dim pFigure As New PathFigure()
            pFigure.StartPoint = New Point(10, 100)
            Dim pBezierSegment As New PolyBezierSegment()
            pBezierSegment.Points.Add(New Point(35, 0))
            pBezierSegment.Points.Add(New Point(135, 0))
            pBezierSegment.Points.Add(New Point(160, 100))
            pBezierSegment.Points.Add(New Point(180, 190))
            pBezierSegment.Points.Add(New Point(285, 200))
            pBezierSegment.Points.Add(New Point(310, 100))
            pFigure.Segments.Add(pBezierSegment)
            animationPath.Figures.Add(pFigure)

            ' Freeze the PathGeometry for performance benefits.
            animationPath.Freeze()

            ' Create a MatrixAnimationUsingPath to move the
            ' button along the path by animating
            ' its MatrixTransform.
            Dim matrixAnimation As New MatrixAnimationUsingPath()
            matrixAnimation.PathGeometry = animationPath

            ' Set IsOffsetCumulative to true so that the animation
            ' values accumulate when its repeats. 
            matrixAnimation.IsOffsetCumulative = True
            matrixAnimation.Duration = TimeSpan.FromSeconds(5)
            matrixAnimation.RepeatBehavior = New RepeatBehavior(2)

            ' Set the animation to target the Matrix property
            ' of the MatrixTransform named "ButtonMatrixTransform".
            Storyboard.SetTargetName(matrixAnimation, "ButtonMatrixTransform")
            Storyboard.SetTargetProperty(matrixAnimation, New PropertyPath(MatrixTransform.MatrixProperty))

            ' Create a Storyboard to contain and apply the animation.
            Dim pathAnimationStoryboard As New Storyboard()
            pathAnimationStoryboard.Children.Add(matrixAnimation)

            ' Start the animation when the button is clicked.
            AddHandler aButton.Click, Sub(sender As Object, e As RoutedEventArgs) pathAnimationStoryboard.Begin(Me)

        End Sub
    End Class
End Namespace

Tenga en cuenta que, aunque la propiedad IsOffsetCumulative hace que los valores de desplazamiento se acumulen con las repeticiones, no hace que los valores de rotación se acumulen. Para que los valores de rotación se acumulen, establezca las propiedades DoesRotateWithTangent y IsAngleCumulative de la animación en true.

Para obtener el ejemplo completo, vea Ejemplo de animación de trayectoria. Para obtener un ejemplo en el que se muestra cómo animar un Matrix valor a lo largo de una ruta de acceso sin acumulación de desplazamiento, vea Animar un objeto a lo largo de una ruta de acceso (animación de matriz).

Consulte también