Calculate ViewBox ScaleFactor on a Metro Style App

Question

Is there any way to get the scale factor by which a ViewBox scales its content in a XAML Windows 8 Metro Style App

Answer 1

The WinRTXAMLToolit has an extension for this.

public static double GetChildScaleX(this Viewbox viewbox)
{
    if (viewbox.Child == null)
        throw new InvalidOperationException("Can't tell effective scale of a Viewbox child for a Viewbox with no child.");

    var fe = viewbox.Child as FrameworkElement;

    if (fe == null)
        throw new InvalidOperationException("Can't tell effective scale of a Viewbox child for a Viewbox with a child that is not a FrameworkElement.");

    if (fe.ActualWidth == 0)
        throw new InvalidOperationException("Can't tell effective scale of a Viewbox child for a Viewbox with a child that is not laid out.");

    return viewbox.ActualWidth / fe.ActualWidth;
}

GetChildScaleY is the same, but with Heights.