public void CalculateMinAndMax() {
var kh = TargetHeight / TotalHeight;
var kw = TargetWidth / TotalWidth;
var k = Math.Min(kh, kw);
MaxWidth = TotalWidth * k / kh;
MaxHeight = TotalHeight * k / kw;
MinWidth = Math.Min(TargetWidth, MaxWidth*0.75);
MinHeight = Math.Min(TargetHeight, MaxHeight*0.75);
}
}