Como animar cor usando quadros-chave

Este exemplo mostra como animar o Color de um SolidColorBrush usando quadros-chave.

Exemplo

O exemplo a seguir usa a classe para animar a ColorAnimationUsingKeyFramesColor propriedade de um SolidColorBrusharquivo . Essa animação usa três quadros-chave da seguinte maneira:

  1. Durante os dois primeiros segundos, usa uma instância da LinearColorKeyFrame classe para alterar gradualmente a cor de verde para vermelho. Quadros-chave lineares como LinearColorKeyFrame criar uma transição linear suave entre valores.

  2. Durante o final do próximo meio segundo, usa uma instância da DiscreteColorKeyFrame classe para alterar rapidamente a cor de vermelho para amarelo. Quadros-chave discretos como DiscreteColorKeyFrame criar mudanças repentinas entre valores, ou seja, a mudança de cor nessa parte da animação ocorre rapidamente e não é sutil.

  3. Durante os dois segundos finais, usa uma instância da SplineColorKeyFrame classe para alterar a cor novamente, desta vez de amarelo de volta para verde. Quadros de chave spline como SplineColorKeyFrame criar uma transição variável entre valores de acordo com os valores da KeySpline propriedade. Neste exemplo, a alteração na cor começa lentamente e acelera exponencialmente na direção do final do segmento de tempo.

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

namespace Microsoft.Samples.KeyFrameExamples
{
    public class ColorAnimationUsingKeyFramesExample : Page
    {
        public ColorAnimationUsingKeyFramesExample()
        {
            Title = "BooleanAnimationUsingKeyFrames Example";
            Background = Brushes.White;
            Margin = new Thickness(20);

            // Create a NameScope for this page so that
            // Storyboards can be used.
            NameScope.SetNameScope(this, new NameScope());

            StackPanel myStackPanel = new StackPanel();
            myStackPanel.Orientation = Orientation.Vertical;
            myStackPanel.HorizontalAlignment = HorizontalAlignment.Center;

            // Create the Border that is the target of the animation.
            SolidColorBrush animatedBrush = new SolidColorBrush();
            animatedBrush.Color = Color.FromArgb(255, 0, 255, 0);
            Border myBorder = new Border();

            // Set the initial color of the border to green.
            myBorder.BorderBrush = animatedBrush;
            myBorder.BorderThickness = new Thickness(28);
            myBorder.Padding = new Thickness(20);
            myStackPanel.Children.Add(myBorder);

            // Create a TextBlock to host inside the Border.
            TextBlock myTextBlock = new TextBlock();
            myTextBlock.Text = "This example shows how to use the ColorAnimationUsingKeyFrames"
                               + " to create an animation on the BorderBrush property of a Border.";
            myBorder.Child = myTextBlock;

            // Assign the Brush a name so that
            // it can be targeted by a Storyboard.
            this.RegisterName(
                "AnimatedBrush", animatedBrush);

            // Create a ColorAnimationUsingKeyFrames to
            // animate the BorderBrush property of the Button.
            ColorAnimationUsingKeyFrames colorAnimation
                = new ColorAnimationUsingKeyFrames();
            colorAnimation.Duration = TimeSpan.FromSeconds(6);

            // Create brushes to use as animation values.
            Color redColor = new Color();
            redColor = Color.FromArgb(255, 255, 0, 0);
            Color yellowColor = new Color();
            yellowColor = Color.FromArgb(255, 255, 255, 0);
            Color greenColor = new Color();
            greenColor = Color.FromArgb(255, 0, 255, 0);

            // Go from green to red in the first 2 seconds. LinearColorKeyFrame creates
            // a smooth, linear animation between values.
            colorAnimation.KeyFrames.Add(
                new LinearColorKeyFrame(
                    redColor, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.0))) // KeyTime
                );

            // In the next half second, go to yellow. DiscreteColorKeyFrame creates a
            // sudden jump between values.
            colorAnimation.KeyFrames.Add(
                new DiscreteColorKeyFrame(
                    yellowColor, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5))) // KeyTime
                );

            // In the final 2 seconds of the animation, go from yellow back to green. SplineColorKeyFrame
            // creates a variable transition between values depending on the KeySpline property. In this example,
            // the animation starts off slow but toward the end of the time segment, it speeds up exponentially.
            colorAnimation.KeyFrames.Add(
                new SplineColorKeyFrame(
                    greenColor, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4.5)), // KeyTime
                    new KeySpline(0.6, 0.0, 0.9, 0.0) // KeySpline
                    )
                );

            // Set the animation to repeat forever.
            colorAnimation.RepeatBehavior = RepeatBehavior.Forever;

            // Set the animation to target the Color property
            // of the object named "AnimatedBrush".
            Storyboard.SetTargetName(colorAnimation, "AnimatedBrush");
            Storyboard.SetTargetProperty(
                colorAnimation, new PropertyPath(SolidColorBrush.ColorProperty));

            // Create a storyboard to apply the animation.
            Storyboard myStoryboard = new Storyboard();
            myStoryboard.Children.Add(colorAnimation);

            // Start the storyboard when the Border loads.
            myBorder.Loaded += delegate(object sender, RoutedEventArgs e)
            {
                myStoryboard.Begin(this);
            };

            Content = myStackPanel;
        }
    }
}

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

Namespace Microsoft.Samples.KeyFrameExamples
    Public Class ColorAnimationUsingKeyFramesExample
        Inherits Page
        Public Sub New()
            Title = "BooleanAnimationUsingKeyFrames Example"
            Background = Brushes.White
            Margin = New Thickness(20)

            ' Create a NameScope for this page so that
            ' Storyboards can be used.
            NameScope.SetNameScope(Me, New NameScope())

            Dim myStackPanel As New StackPanel()
            myStackPanel.Orientation = Orientation.Vertical
            myStackPanel.HorizontalAlignment = HorizontalAlignment.Center

            ' Create the Border that is the target of the animation.
            Dim animatedBrush As New SolidColorBrush()
            animatedBrush.Color = Color.FromArgb(255, 0, 255, 0)
            Dim myBorder As New Border()

            ' Set the initial color of the border to green.
            myBorder.BorderBrush = animatedBrush
            myBorder.BorderThickness = New Thickness(28)
            myBorder.Padding = New Thickness(20)
            myStackPanel.Children.Add(myBorder)

            ' Create a TextBlock to host inside the Border.
            Dim myTextBlock As New TextBlock()
            myTextBlock.Text = "This example shows how to use the ColorAnimationUsingKeyFrames" & " to create an animation on the BorderBrush property of a Border."
            myBorder.Child = myTextBlock

            ' Assign the Brush a name so that
            ' it can be targeted by a Storyboard.
            Me.RegisterName("AnimatedBrush", animatedBrush)

            ' Create a ColorAnimationUsingKeyFrames to
            ' animate the BorderBrush property of the Button.
            Dim colorAnimation As New ColorAnimationUsingKeyFrames()
            colorAnimation.Duration = TimeSpan.FromSeconds(6)

            ' Create brushes to use as animation values.
            Dim redColor As New Color()
            redColor = Color.FromArgb(255, 255, 0, 0)
            Dim yellowColor As New Color()
            yellowColor = Color.FromArgb(255, 255, 255, 0)
            Dim greenColor As New Color()
            greenColor = Color.FromArgb(255, 0, 255, 0)

            ' Go from green to red in the first 2 seconds. LinearColorKeyFrame creates
            ' a smooth, linear animation between values.
            colorAnimation.KeyFrames.Add(New LinearColorKeyFrame(redColor, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.0)))) ' KeyTime -  Target value (KeyValue)

            ' In the next half second, go to yellow. DiscreteColorKeyFrame creates a 
            ' sudden jump between values.
            colorAnimation.KeyFrames.Add(New DiscreteColorKeyFrame(yellowColor, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.5)))) ' KeyTime -  Target value (KeyValue)

            ' In the final 2 seconds of the animation, go from yellow back to green. SplineColorKeyFrame 
            ' creates a variable transition between values depending on the KeySpline property. In this example,
            ' the animation starts off slow but toward the end of the time segment, it speeds up exponentially.
            colorAnimation.KeyFrames.Add(New SplineColorKeyFrame(greenColor, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4.5)), New KeySpline(0.6, 0.0, 0.9, 0.0))) ' KeySpline -  KeyTime -  Target value (KeyValue)

            ' Set the animation to repeat forever. 
            colorAnimation.RepeatBehavior = RepeatBehavior.Forever

            ' Set the animation to target the Color property
            ' of the object named "AnimatedBrush".
            Storyboard.SetTargetName(colorAnimation, "AnimatedBrush")
            Storyboard.SetTargetProperty(colorAnimation, New PropertyPath(SolidColorBrush.ColorProperty))

            ' Create a storyboard to apply the animation.
            Dim myStoryboard As New Storyboard()
            myStoryboard.Children.Add(colorAnimation)

            ' Start the storyboard when the Border loads.
            AddHandler myBorder.Loaded, Sub(sender As Object, e As RoutedEventArgs) myStoryboard.Begin(Me)

            Content = myStackPanel
        End Sub

    End Class
End Namespace
<Page  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="ThicknessAnimationUsingKeyFrames Example">

  <StackPanel Orientation="Vertical" HorizontalAlignment="Center">
    <Border Background="#99FFFFFF"  BorderThickness="28"
    Margin="0,60,0,20" Padding="20" >
      <Border.BorderBrush>
        <SolidColorBrush x:Name="MyAnimatedBrush" Color="Green" />
      </Border.BorderBrush>
      <Border.Triggers>
        <EventTrigger RoutedEvent="Border.Loaded">
          <BeginStoryboard>
            <Storyboard>

              <!-- Animate from green to red using a linear key frame, from red to 
              yellow using a discrete key frame, and from yellow back to green with
              a spline key frame. This animation repeats forever. -->
              <ColorAnimationUsingKeyFrames
                Storyboard.TargetProperty="Color"
                Storyboard.TargetName="MyAnimatedBrush"
                Duration="0:0:6" FillBehavior="HoldEnd" RepeatBehavior="Forever">
                <ColorAnimationUsingKeyFrames.KeyFrames>

                  <!-- Go from green to red in the first 2 seconds. LinearColorKeyFrame creates
                  a smooth, linear animation between values. -->
                  <LinearColorKeyFrame Value="Red" KeyTime="0:0:2" />

                  <!-- In the next half second, go to yellow. DiscreteColorKeyFrame creates a 
                  sudden jump between values. -->
                  <DiscreteColorKeyFrame Value="Yellow" KeyTime="0:0:2.5" />

                  <!-- In the final 2 seconds of the animation, go from yellow back to green. SplineColorKeyFrame 
                  creates a variable transition between values depending on the KeySpline property. In this example,
                  the animation starts off slow but toward the end of the time segment, it speeds up exponentially.-->
                  <SplineColorKeyFrame Value="Green" KeyTime="0:0:4.5" KeySpline="0.6,0.0 0.9,0.00" />
                </ColorAnimationUsingKeyFrames.KeyFrames>
              </ColorAnimationUsingKeyFrames>
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Border.Triggers>

      <TextBlock>
        This example shows how to use the ColorAnimationUsingKeyFrames to create
        an animation on the BorderBrush property of a Border.
      </TextBlock>
    </Border>

  </StackPanel>
</Page>

Para ver o exemplo completo, consulte Exemplo de animação de quadro-chave.

Confira também