func (f *Font) Use(cr *cairo.Context, bold bool) { weight := cairo.FontWeightNormal if bold { weight = cairo.FontWeightBold } cr.SelectFontFace(f.Name, cairo.FontSlantNormal, weight) cr.SetFontSize(float64(f.Size)) if f.cw == 0 { f.metricsFromCairo(cr) } }