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Comment : contrôler le minutage d'une animation d'image clé

Mise à jour : novembre 2007

Cet exemple montre comment contrôler le minutage des images clés d'une animation d'image clé. Comme les autres animations, les animations d'image clé ont une propriété Duration. En plus de spécifier la durée d'une animation, vous devez spécifier la partie de cette durée qui sera allouée à chacune de ses images clés. Pour allouer du temps, spécifiez un KeyTime pour chaque image clé de l'animation.

Le KeyTime de chaque image clé spécifie la fin d'une image clé (il ne spécifie pas la durée de lecture d'une image clé). Vous pouvez spécifier un KeyTime comme une valeur TimeSpan, un pourcentage, ou bien la valeur spéciale Uniform ou Paced.

Exemple

L'exemple suivant utilise un DoubleAnimationUsingKeyFrames pour animer un rectangle sur l'écran. Les temps clés des images clés sont définis avec les valeurs TimeSpan.

/*
   This Rectangle is animated with KeyTimes using TimeSpan Values. 
   It moves horizontally to 100 in the first 3 seconds, 100 to 300 in 
   the next second, and 300 to 500 in the last 6 seconds.
*/

// Create the a rectangle.
Rectangle aRectangle = new Rectangle();
aRectangle.Fill = Brushes.Blue;
aRectangle.Stroke = Brushes.Black;
aRectangle.StrokeThickness = 5;
aRectangle.Width = 50;
aRectangle.Height = 50;

// Create a transform to move the rectangle
// across the screen.
TranslateTransform translateTransform1 = 
    new TranslateTransform();
aRectangle.RenderTransform = translateTransform1;

// Create a DoubleAnimationUsingKeyFrames
// to animate the transform.
DoubleAnimationUsingKeyFrames transformAnimation = 
    new DoubleAnimationUsingKeyFrames();
transformAnimation.Duration = TimeSpan.FromSeconds(10);

// Animate to 100 at 3 seconds.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(100, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3))));

// Animate to 300 at 4 seconds.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(300, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4))));

// Animate to 500 at 10 seconds.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(500, KeyTime.FromTimeSpan(TimeSpan.FromSeconds(10))));

// Start the animation when the rectangle is loaded.
aRectangle.Loaded += delegate(object sender, RoutedEventArgs e)
{
    translateTransform1.BeginAnimation(TranslateTransform.XProperty, transformAnimation);
};

<!-- This Rectangle is animated with KeyTimes using TimeSpan Values. 
     It moves horizontally to 100 in the first 3 seconds, 100 to 300 in 
     the next second, and 300 to 500 in the last 6 seconds. -->
<Rectangle Fill="Blue" Stroke="Black" StrokeThickness="5"
  Width="50" Height="50">
  <Rectangle.RenderTransform>
    <TranslateTransform x:Name="TranslateTransform1" />
  </Rectangle.RenderTransform>
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.Loaded">
      <BeginStoryboard>
        <Storyboard>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetName="TranslateTransform1" 
            Storyboard.TargetProperty="X"
            Duration="0:0:10">

            <!-- These KeyTime properties are specified as TimeSpan values 
                 which are in the form of "hours:minutes:seconds". -->
            <LinearDoubleKeyFrame Value="100" KeyTime="0:0:3" />
            <LinearDoubleKeyFrame Value="300" KeyTime="0:0:4" />
            <LinearDoubleKeyFrame Value="500" KeyTime="0:0:10" />
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

L'illustration suivante montre le moment où la valeur de chaque image clé est atteinte.

Valeurs de clés atteintes à 3, 4 et 10 secondes

L'exemple suivant montre une animation identique, mais dont les temps clés des images clés sont définis avec des valeurs exprimées en pourcentage.

/*
  This rectangle moves horizontally to 100 in the first 3 seconds, 
  100 to 300 in  the next second, and 300 to 500 in the last 6 seconds.
*/

// Create the a rectangle.
Rectangle aRectangle = new Rectangle();
aRectangle.Fill = Brushes.Purple;
aRectangle.Stroke = Brushes.Black;
aRectangle.StrokeThickness = 5;
aRectangle.Width = 50;
aRectangle.Height = 50;

// Create a transform to move the rectangle
// across the screen.
TranslateTransform translateTransform2 =
    new TranslateTransform();
aRectangle.RenderTransform = translateTransform2;

// Create a DoubleAnimationUsingKeyFrames
// to animate the transform.
DoubleAnimationUsingKeyFrames transformAnimation =
    new DoubleAnimationUsingKeyFrames();
transformAnimation.Duration = TimeSpan.FromSeconds(10);

// Animate to 100 at 30% of the animation's duration.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(100, KeyTime.FromPercent(0.3)));

// Animate to 300 at 40% of the animation's duration.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(300, KeyTime.FromPercent(0.4)));

// Animate to 500 at 100% of the animation's duration.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(500, KeyTime.FromPercent(1.0)));

// Start the animation when the rectangle is loaded.
aRectangle.Loaded += delegate(object sender, RoutedEventArgs e)
{
    translateTransform2.BeginAnimation(TranslateTransform.XProperty, transformAnimation);
};
<!-- This rectangle moves horizontally to 100 in the first 3 seconds, 
     100 to 300 in  the next second, and 300 to 500 in the last 6 seconds.-->
<Rectangle Fill="Purple" Stroke="Black" StrokeThickness="5"
  Width="50" Height="50">
  <Rectangle.RenderTransform>
    <TranslateTransform x:Name="TranslateTransform2" />
  </Rectangle.RenderTransform>
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.Loaded">
      <BeginStoryboard>
        <Storyboard>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetName="TranslateTransform2" 
            Storyboard.TargetProperty="X"
            Duration="0:0:10">

            <!-- KeyTime properties are expressed as Percentages. -->
            <LinearDoubleKeyFrame Value="100" KeyTime="30%" />
            <LinearDoubleKeyFrame Value="300" KeyTime="40%" />
            <LinearDoubleKeyFrame Value="500" KeyTime="100%" />
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

L'illustration suivante montre le moment où la valeur de chaque image clé est atteinte.

Valeurs de clés atteintes à 3, 4 et 10 secondes

L'exemple suivant utilise des valeurs de temps clé Uniform.

/*
   This rectangle is animated with KeyTimes using Uniform values. 
   Goes to 100 in the first 3.3 seconds, 100 to
   300 in the next 3.3 seconds, 300 to 500 in the last 3.3 seconds.
*/

// Create the a rectangle.
Rectangle aRectangle = new Rectangle();
aRectangle.Fill = Brushes.Red;
aRectangle.Stroke = Brushes.Black;
aRectangle.StrokeThickness = 5;
aRectangle.Width = 50;
aRectangle.Height = 50;

// Create a transform to move the rectangle
// across the screen.
TranslateTransform translateTransform3 =
    new TranslateTransform();
aRectangle.RenderTransform = translateTransform3;

// Create a DoubleAnimationUsingKeyFrames
// to animate the transform.
DoubleAnimationUsingKeyFrames transformAnimation =
    new DoubleAnimationUsingKeyFrames();
transformAnimation.Duration = TimeSpan.FromSeconds(10);

/*
   KeyTime properties are expressed with values of Uniform. When a key time is set to
   "Uniform" the total allotted time of the animation is divided evenly between key frames.  
   In this example, the total duration of the animation is ten seconds and there are four 
   key frames each of which are set to "Uniform", therefore, the duration of each key frame 
   is 3.3 seconds (10/3).
 */

// Animate to 100.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(100, KeyTime.Uniform));

// Animate to 300.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(300, KeyTime.Uniform));

// Animate to 500.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(500, KeyTime.Uniform));

// Start the animation when the rectangle is loaded.
aRectangle.Loaded += delegate(object sender, RoutedEventArgs e)
{
    translateTransform3.BeginAnimation(TranslateTransform.XProperty, transformAnimation);
};

<!-- This rectangle is animated with KeyTimes using Uniform values. 
     Goes to 100 in the first 3.3 seconds, 100 to
     300 in the next 3.3 seconds, 300 to 500 in the last 3.3 seconds. -->
<Rectangle Fill="Red" Stroke="Black" StrokeThickness="5"
  Width="50" Height="50">
  <Rectangle.RenderTransform>
    <TranslateTransform x:Name="TranslateTransform3" />
  </Rectangle.RenderTransform>
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.Loaded">
      <BeginStoryboard>
        <Storyboard>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetName="TranslateTransform3" 
            Storyboard.TargetProperty="X"
            Duration="0:0:10">

            <!--   KeyTime properties are expressed with values of Uniform. When a key time is set to
                   "Uniform" the total allotted time of the animation is divided evenly between key frames.  
                   In this example, the total duration of the animation is ten seconds and there are four 
                   key frames each of which are set to "Uniform", therefore, the duration of each key frame 
                   is 3.3 seconds (10/3). -->
            <LinearDoubleKeyFrame Value="100" KeyTime="Uniform" />
            <LinearDoubleKeyFrame Value="300" KeyTime="Uniform" />
            <LinearDoubleKeyFrame Value="500" KeyTime="Uniform" />
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

L'illustration suivante montre le moment où la valeur de chaque image clé est atteinte.

Valeurs de clés atteintes à 3,3, 6,6 et 9,9 secondes

Le dernier exemple utilise des valeurs de temps clé Paced.

/*
   This rectangle is animated with KeyTimes using Paced Values. 
   The rectangle moves between key frames at uniform rate except for first key frame
   because using a Paced value on the first KeyFrame in a collection of frames gives a time of zero.
*/

// Create the a rectangle.
Rectangle aRectangle = new Rectangle();
aRectangle.Fill = Brushes.Orange;
aRectangle.Stroke = Brushes.Black;
aRectangle.StrokeThickness = 5;
aRectangle.Width = 50;
aRectangle.Height = 50;

// Create a transform to move the rectangle
// across the screen.
TranslateTransform translateTransform4 =
    new TranslateTransform();
aRectangle.RenderTransform = translateTransform4;

// Create a DoubleAnimationUsingKeyFrames
// to animate the transform.
DoubleAnimationUsingKeyFrames transformAnimation =
    new DoubleAnimationUsingKeyFrames();
transformAnimation.Duration = TimeSpan.FromSeconds(10);

/*
   Use Paced values when a constant rate is desired. 
   The time allocated to a key frame with a KeyTime of "Paced" is
   determined by the time allocated to the other key frames of the animation. This time is 
   calculated to attempt to give a "paced" or "constant velocity" for the animation.
 */

// Animate to 100.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(100, KeyTime.Paced));

// Animate to 300.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(300, KeyTime.Paced));

// Animate to 500.
transformAnimation.KeyFrames.Add(
    new LinearDoubleKeyFrame(500, KeyTime.Paced));

// Start the animation when the rectangle is loaded.
aRectangle.Loaded += delegate(object sender, RoutedEventArgs e)
{
    translateTransform4.BeginAnimation(TranslateTransform.XProperty, transformAnimation);
};

<!-- This rectangle is animated with KeyTimes using Paced Values. 
     The rectangle moves between key frames at uniform rate except for first key frame
     because using a Paced value on the first KeyFrame in a collection of frames gives a time of zero. -->
<Rectangle Fill="Orange" Stroke="Black" StrokeThickness="5"
  Width="50" Height="50">
  <Rectangle.RenderTransform>
    <TranslateTransform x:Name="TranslateTransform4" />
  </Rectangle.RenderTransform>
  <Rectangle.Triggers>
    <EventTrigger RoutedEvent="Rectangle.Loaded">
      <BeginStoryboard>
        <Storyboard>
          <DoubleAnimationUsingKeyFrames 
            Storyboard.TargetName="TranslateTransform4" 
            Storyboard.TargetProperty="X"
            Duration="0:0:10">

            <!-- Use Paced values when a constant rate is desired. 
                 The time allocated to a key frame with a KeyTime of "Paced" is
                 determined by the time allocated to the other key frames of the animation. This time is 
                 calculated to attempt to give a "paced" or "constant velocity" for the animation. -->
            <LinearDoubleKeyFrame Value="100" KeyTime="Paced" />
            <LinearDoubleKeyFrame Value="300" KeyTime="Paced" />
            <LinearDoubleKeyFrame Value="500" KeyTime="Paced" />
          </DoubleAnimationUsingKeyFrames>
        </Storyboard>
      </BeginStoryboard>
    </EventTrigger>
  </Rectangle.Triggers>
</Rectangle>

L'illustration suivante montre le moment où la valeur de chaque image clé est atteinte.

Valeurs de clés atteintes à 0, 5 et 10 secondes

Par souci de simplicité, les versions de code de cet exemple utilisent des animations locales, et non des storyboards, car on applique une seule animation par propriété. Toutefois, les exemples peuvent être modifiés pour utiliser plutôt des storyboards. Pour obtenir un exemple sur la manière de déclarer un storyboard dans le code, consultez Comment : animer une propriété à l'aide d'une table de montage séquentiel.

Pour l'exemple complet, consultez Animation d'image clé, exemple. Pour plus d'informations sur les animations d'image clé, consultez Vue d'ensemble des animations d'image clé.

Voir aussi

Concepts

Vue d'ensemble des animations d'image clé

Vue d'ensemble de l'animation

Autres ressources

Exemples d'animation et de minutage

Rubriques Comment relatives à l'animation et au minutage