Cómo: Animar un objeto a lo largo de un trazado (animación en matriz con acumulación de desplazamiento)

En este ejemplo se muestra cómo usar la clase MatrixAnimationUsingPath para animar un objeto a lo largo de un trazado y hacer que la 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 una clase MatrixTransform aplicada a un botón. Como resultado, un botón se mueve a lo largo de un trazado curvo.

Además, el ejemplo establece la propiedad IsOffsetCumulative en true, lo que causa que el desplazamiento de la matriz animada a se acumule según la animación se repite. Dado que el desplazamiento se acumula, el botón se aleja por la pantalla cuando se repite la animación, en lugar de restablecerse a 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 cause que los valores de desplazamiento se acumulen con las repeticiones, no lo hace con los valores de rotación. Para que los valores de rotación se acumulen, establezca las propiedades DoesRotateWithTangent y IsAngleCumulative de la animación en true.

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

Vea también

• Información general sobre animaciones
• Temas "Cómo..." de animación de trazado