It's hard to be sure exactly the animation you want. So I put together a few that will likely give you what you want. Just paste this into a page and run it.
<Page.Resources>
<Storyboard x:Name="RevealImages">
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" Storyboard.TargetName="rectangle">
<EasingDoubleKeyFrame KeyTime="0" Value="-300"/>
<EasingDoubleKeyFrame KeyTime="0:0:1" Value="0">
<EasingDoubleKeyFrame.EasingFunction>
<CubicEase EasingMode="EaseInOut"/>
</EasingDoubleKeyFrame.EasingFunction>
</EasingDoubleKeyFrame>
<EasingDoubleKeyFrame KeyTime="0:0:2" Value="0"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="-300"/>
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateX)" Storyboard.TargetName="rectangle1">
<EasingDoubleKeyFrame KeyTime="0:0:1" Value="0">
<EasingDoubleKeyFrame.EasingFunction>
<CubicEase EasingMode="EaseInOut"/>
</EasingDoubleKeyFrame.EasingFunction>
</EasingDoubleKeyFrame>
<EasingDoubleKeyFrame KeyTime="0:0:2" Value="0"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="-250"/>
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.TranslateY)" Storyboard.TargetName="rectangle1">
<EasingDoubleKeyFrame KeyTime="0:0:1" Value="0">
<EasingDoubleKeyFrame.EasingFunction>
<CubicEase EasingMode="EaseInOut"/>
</EasingDoubleKeyFrame.EasingFunction>
</EasingDoubleKeyFrame>
<EasingDoubleKeyFrame KeyTime="0:0:2" Value="0"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="250"/>
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="rectangle2">
<EasingDoubleKeyFrame KeyTime="0:0:1" Value="1">
<EasingDoubleKeyFrame.EasingFunction>
<CubicEase EasingMode="EaseInOut"/>
</EasingDoubleKeyFrame.EasingFunction>
</EasingDoubleKeyFrame>
<EasingDoubleKeyFrame KeyTime="0:0:2" Value="1"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="0"/>
</DoubleAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(TextBlock.Text)" Storyboard.TargetName="textBlock">
<DiscreteObjectKeyFrame KeyTime="0" Value="Filling"/>
<DiscreteObjectKeyFrame KeyTime="0:0:1" Value="Waiting"/>
<DiscreteObjectKeyFrame KeyTime="0:0:2" Value="Hiding"/>
<DiscreteObjectKeyFrame KeyTime="0:0:3" Value=""/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(TextBlock.FontFamily)" Storyboard.TargetName="textBlock">
<DiscreteObjectKeyFrame KeyTime="0:0:2">
<DiscreteObjectKeyFrame.Value>
<FontFamily>Global User Interface</FontFamily>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
<DiscreteObjectKeyFrame KeyTime="0:0:3">
<DiscreteObjectKeyFrame.Value>
<FontFamily>Global User Interface</FontFamily>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Button Content="Show" HorizontalAlignment="Left" Height="75" Margin="7,7,0,0" VerticalAlignment="Top" Width="92" FontFamily="Global User Interface">
<Interactivity:Interaction.Behaviors>
<Core:EventTriggerBehavior EventName="Click">
<Media:ControlStoryboardAction Storyboard="{StaticResource RevealImages}"/>
</Core:EventTriggerBehavior>
</Interactivity:Interaction.Behaviors>
</Button>
<Rectangle x:Name="rectangle" HorizontalAlignment="Left" Height="250" Margin="10,117,0,0" VerticalAlignment="Top" Width="250" RenderTransformOrigin="0.5,0.5" Fill="White">
<Rectangle.RenderTransform>
<CompositeTransform TranslateX="-250"/>
</Rectangle.RenderTransform>
</Rectangle>
<Grid HorizontalAlignment="Left" Height="250" Margin="265,117,0,0" VerticalAlignment="Top" Width="250">
<Grid.Clip>
<RectangleGeometry Rect="0,0,250,250" />
</Grid.Clip>
<Rectangle x:Name="rectangle1" Fill="White" RenderTransformOrigin="0.5,0.5" >
<Rectangle.RenderTransform>
<CompositeTransform TranslateX="-250" TranslateY="250"/>
</Rectangle.RenderTransform>
</Rectangle>
</Grid>
<Rectangle x:Name="rectangle2" HorizontalAlignment="Left" Height="250" Margin="520,117,0,0" VerticalAlignment="Top" Width="250" Opacity="0" Fill="White"/>
<TextBlock HorizontalAlignment="Left" Height="28" Margin="10,84,0,0" TextWrapping="Wrap" Text="Slide In" VerticalAlignment="Top" Width="250" FontSize="20"/>
<TextBlock HorizontalAlignment="Left" Height="28" Margin="265,84,0,0" TextWrapping="Wrap" Text="Slip In" VerticalAlignment="Top" Width="250" FontSize="20"/>
<TextBlock HorizontalAlignment="Left" Height="28" Margin="520,84,0,0" TextWrapping="Wrap" Text="Fade In" VerticalAlignment="Top" Width="250" FontSize="20"/>
<TextBlock x:Name="textBlock" HorizontalAlignment="Left" Height="137" Margin="113,10,0,0" TextWrapping="Wrap" Text="0" VerticalAlignment="Top" Width="238" FontSize="66.667"/>
</Grid>
Best of luck!
Storyboardfired off by a routed event likeClickof theButtonto perform a DoubleAnimation to the Opacity where you can also set theDurationmore info, and dont worry about your english, we're all coders no matter our native language ;) - Chris W.