public void SetAttributeTypeface(FontAttributes attribute, Typeface typeface)
        {
            FontFaceInfo item = this[attribute];

            if (item == null)
            {
                item = new FontFaceInfo(this, typeface);
                _fontFaceList.Add(item);
            }

            if (item.TypeFace == null)
            {
                item.TypeFace = typeface;
            }
        }
        public CustomTypefaceSpan GetSpanTypeface(FontAttributes attribute)
        {
            FontFaceInfo item = this[attribute];

            return(item == null ? null : item.SpanTypeFace);
        }
        public Typeface GetTypeface(FontAttributes attribute)
        {
            FontFaceInfo item = this[attribute];

            return(item == null ? null : item.TypeFace);
        }