How to get the coordinate position of an element inside a user control in WPF

For example there is a user control like this:

<UserControl d:DesignHeight="100" d:DesignWidth="200" ...>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="100" />
            <ColumnDefinition Width="100" />
        </Grid.ColumnDefinitions>
        <Ellipse Name="leftEllipse" Grid.Column="0" Width="50" Height="50" HorizontalAlignment="Center" VerticalAlignment="Center" Fill="Red" />
        <Ellipse Name="rightEllipse" Grid.Column="1" Width="50" Height="50" HorizontalAlignment="Center" VerticalAlignment="Center" Fill="Green" />
    </Grid>
</UserControl>

Here is the main window:

<Window ...>
    <Canvas Name="canvas1">
        <my:MyUserControl x:Name="myUserControl1" Width="200" Height="100" Canvas.Top="100" Canvas.Left="100" />
    </Canvas>
</Window>

We know that the coordinate position of the user control itself can be obtained by the following methods:

double x = Canvas.GetLeft(myUserControl1);

So how to get the coordinates of the elements inside the user control? Be aware that when the user control itself applies a transformation (eg: RotateTransform), the coordinates of its internal elements will change.

There are two ways to solve this problem:

//method 1:

Write the method in the user control:

public GeneralTransform LeftEllipseTransform(UIElement e)
{
    return leftEllipse.TransformToAncestor(e);
}

In the main window call:

var p = myUserControl1.LeftEllipseTransform(canvas1).Transform( new Point()); //Get the coordinates of the upper left corner of the left circle

//Method 2:

Write the method in the user control:

public Point GetLeftEllipsePosition(Point p, UIElement e)
{
    return leftEllipse.TranslatePoint(p, e);
}

In the main window call:

var p = myUserControl1.GetLeftEllipsePosition( new Point(), canvas1); //Get the coordinates of the upper left corner of the left circle

Or, if you want to get the center position of the left circle, call it like this:

var p = myUserControl1.GetLeftEllipsePosition( new Point( 25 , 25 ), canvas1); //Get the coordinates of the center of the left circle