public void ToggleAutoFitMode()
{
switch (AutoFitMode)
{
case AutoFitMode.None:
AutoFitMode = AutoFitMode.Extent;
break;
case AutoFitMode.Extent:
AutoFitMode = AutoFitMode.Fill;
break;
case AutoFitMode.Fill:
AutoFitMode = AutoFitMode.None;
break;
}
}