/// <summary>
/// Handler for the ManipulationDelta event. It may or may not be a pinch. If it is not a
/// pinch, the ViewportControl will take care of it.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void OnManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{
if (e.PinchManipulation != null)
{
e.Handled = true;
if (!_pinching)
{
_pinching = true;
Point center = e.PinchManipulation.Original.Center;
_relativeMidpoint = new Point(center.X / TestImage.ActualWidth, center.Y / TestImage.ActualHeight);
var xform = TestImage.TransformToVisual(viewport);
_screenMidpoint = xform.Transform(center);
}
_scale = _originalScale * e.PinchManipulation.CumulativeScale;
CoerceScale(false);
ResizeImage(false);
}
else if (_pinching)
{
_pinching = false;
_originalScale = _scale = _coercedScale;
}
}