private void ZoomControl_MouseWheel(object sender, MouseWheelEventArgs e)
{
double deltaZoom = GetZoomDelta(e.Delta);
double width = zoomControl.ActualWidth * deltaZoom;
double height = zoomControl.ActualHeight * deltaZoom;
Point cursorPosition = e.GetPosition(zoomControl);
double currentRelativeLeft = cursorPosition.X / zoomControl.ActualWidth;
double currentRelativeTop = cursorPosition.Y / zoomControl.ActualHeight;
var topLeftCorner = new Point(
cursorPosition.X - width * currentRelativeLeft,
cursorPosition.Y - height * currentRelativeTop);
var newSize = new Size(width, height);
var zoomTo = new Rect(topLeftCorner, newSize);
zoomControl.ZoomTo(zoomTo);
e.Handled = true;
}
