def font_size
      return sz if sz
      font = styles.fonts[styles.cellXfs[style].fontId] || styles.fonts[0]
      (font.b || (defined?(@b) && @b)) ? (font.sz * 1.5) : font.sz
    end
def font_size
      return sz if sz
      font = styles.fonts[styles.cellXfs[style].fontId] || styles.fonts[0]
      (font.b || (defined?(@b) && @b)) ? (font.sz * 1.5) : font.sz
    end
we scale the font size if bold style is applied to either the style font or
 the cell itself. Yes, it is a bit of a hack, but it is much better than using
 imagemagick and loading metrics for every character.