public Size Measure(char[] charBuffer, int startAt, int len)
 {
     _textPrinter.FontSizeInPoints = this.FontSize;
     float width;
     float height;
     _textPrinter.Measure(charBuffer, startAt, len, out width, out height);
     return new Size(width, height);
 }
 public Size Measure(char[] charBuffer, int startAt, int len)
 {
     _textPrinter.FontSizeInPoints = this.FontSize;
     Typography.TextLayout.MeasuredStringBox mesureStringBox = _textPrinter.Measure(charBuffer, startAt, len);
     return(new Size(mesureStringBox.width, mesureStringBox.btbd));
 }