public void StartPinchToZoom(float x0, float y0, float x1, float y1)
{
_previousDist = LineUtil.Distance(x0, y0, x1, y1);
if (_previousDist > _minPinchToZoomDistance)
{
_savedMatrix.Set(_matrix);
LineUtil.Middle(ref _middle, x0, y0, x1, y1);
}
}
