code: func (f *Fpdf) SetLineJoinStyle(styleStr string) {
  	var joinStyle int
  	switch styleStr {
  	case "round":
  		joinStyle = 1
  	case "bevel":
  		joinStyle = 2
  	default:
  		joinStyle = 0
  	}
  	f.joinStyle = joinStyle
  	if f.page > 0 {
  		f.outf("%d j", f.joinStyle)
  	}
  }
docs: // SetLineJoinStyle defines the line cap style. styleStr should be "miter",
  // "round" or "bevel". The method can be called before the first page
  // is created. The value is retained from page to page.