static void Main(string[] args)
{
Size size = new Size(5, 4);
Size newSize = GetRotatedSize(size, Math.PI/4);
Console.WriteLine("New width: {0:F2}", newSize.width);
Console.WriteLine("New height: {0:F2}", newSize.height);
}
public static Size GetRotatedSize(Size size, double angleOfRotation)
{
double newWidth = Math.Abs(Math.Cos(angleOfRotation)) * size.width +
Math.Abs(Math.Sin(angleOfRotation)) * size.height;
double newHeight = Math.Abs(Math.Sin(angleOfRotation)) * size.width +
Math.Abs(Math.Cos(angleOfRotation)) * size.height;
return new Size(newWidth, newHeight);
}