OpacityMask on Image in windows phone 8.1 - windows-runtime

Question

In a windows phone 8.1 runtime app I need to crop an image using a circle, to doing this i have used this code:
<Ellipse x:Name="ellipse" Stroke="White" StrokeThickness="1" StrokeDashArray="3,3" Height="300" Width="300" Canvas.ZIndex="1" VerticalAlignment="Center" HorizontalAlignment="Center" >
<Ellipse.Fill>
<ImageBrush Stretch="UniformToFill" ImageSource="{Binding Source, ElementName=image}"/>
</Ellipse.Fill>
</Ellipse>
<Grid Background="Black" >
<Image x:Name="image" Source="ms-appx:///Assets/avatar.png" VerticalAlignment="Center" Stretch="UniformToFill" HorizontalAlignment="Center" Height="300" Opacity="0.5" />
</Grid>
this is the result:
for render the ellipse i use this code:
var bitmap = new RenderTargetBitmap();
await bitmap.RenderAsync(ellipse);
I have to let the user translate and zoom this image, how can i manipulate those 2 images in a way that they looks one image?

Answer 1

Ok so after variour research and various test this is the solution to my problem.
With tis code you can handle full manipulation event including rotation zoom and translation!
XAML:
<Grid x:Name="LayoutRoot" Background="Black">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition/>
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Grid.Row="1" x:Name="ContentRoot" RenderTransformOrigin="0.5,0.5" Opacity="0.5" >
<Image x:Name="Image" Source="ms-appx:///Assets/AccountManagement/avatar.png" VerticalAlignment="Center" Stretch="UniformToFill" ScrollViewer.HorizontalScrollBarVisibility="Visible" HorizontalAlignment="Center" Height="300" RenderTransformOrigin="0.5,0.5" >
<Image.RenderTransform>
<CompositeTransform x:Name="ImageCompositeTransform" Rotation="0" TranslateX="0" TranslateY="0" ScaleX="1" ScaleY="1" />
</Image.RenderTransform>
</Image>
</Grid>
<Ellipse ManipulationDelta="Ellipse_ManipulationDelta" x:Name="Ellipse" Stroke="White" StrokeThickness="1" StrokeDashArray="3,3" Height="300" Width="300" Canvas.ZIndex="1" Margin="0" Grid.Row="1" VerticalAlignment="Center" d:LayoutOverrides="Height" HorizontalAlignment="Center" ManipulationMode="All" RenderTransformOrigin="0.5,0.5" >
<Ellipse.Fill>
<ImageBrush Stretch="UniformToFill" ImageSource="{Binding Source, ElementName=Image}">
<ImageBrush.Transform>
<CompositeTransform CenterX="150" CenterY="150" ScaleX="{Binding ScaleX, ElementName=ImageCompositeTransform}" ScaleY="{Binding ScaleY, ElementName=ImageCompositeTransform}" TranslateX="{Binding TranslateX, ElementName=ImageCompositeTransform}" TranslateY="{Binding TranslateY, ElementName=ImageCompositeTransform}" Rotation="{Binding Rotation, ElementName=ImageCompositeTransform}" />
</ImageBrush.Transform>
</ImageBrush>
</Ellipse.Fill>
</Ellipse>
</Grid>
C#:
private void Ellipse_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
{
ImageCompositeTransform.ScaleX *= e.Delta.Scale;
ImageCompositeTransform.ScaleY *= e.Delta.Scale;
ImageCompositeTransform.Rotation += e.Delta.Rotation / Math.PI;
ImageCompositeTransform.TranslateX += e.Delta.Translation.X;
ImageCompositeTransform.TranslateY += e.Delta.Translation.Y;
}