private void targetImage_PreviewContactDown(object sender, ContactEventArgs e)
{
if (!e.Contact.IsFingerRecognized)
{
return;
}
e.Contact.Capture(targetImage, System.Windows.Input.CaptureMode.SubTree);
manipulationProcessor.BeginTrack(e.Contact);
e.Handled = true;
downContacts.Add(e.Contact);
}
