protected int NextColour()
 {
     if (colour != null)
     {
         return(colour.FaceColour());
     }
     return(0);
 }
        /// <summary>
        /// 设置颜色
        /// </summary>
        public void SetColour()
        {
            AbstractFaceSlopeColour colour = FaceSlopeColourBuilder.Build(this);
            int cr = colour.FaceColour();

            if (cr != 0)
            {
                this.Face.Color = cr;
            }
        }