/// <summary>
 /// 将 <see cref="Dxa"/> 单位转换为 <see cref="Pt"/> 单位。
 /// </summary>
 public static Pt ToPt(this Dxa dxa)
 {
     return(new Pt(dxa.Value / 20));
 }
 public static Inch ToInch(this Dxa dxa)
 {
     return(new Inch(dxa.Value / 72));
 }
 public static Emu ToEmu(this Dxa dxa)
 {
     return(new Emu(dxa.Value * 635));
 }