R 如何使用spplot更改字体系列？

请您建议如何使用spplot更改字体系列？我一直在寻找，并尝试了许多方法，如：

trellis.par.set(fontfamily = "mono", family = "mono")
spplot(xxKv[,"value"], 
    main=list(label="Testfont Jilm JILM",cex=3),
    par.settings = list(fontfamily = "mono"),
    family = "mono",
    fontfamily = "mono",
    labels = list(fontfamily = "mono")
)

但没有效果。

---

谢谢大家!

啊哈，这只是一个随机实验

spplot(xxKv[,"value"], 
    main=list(label="Testfont Jilm JILM",cex=3,fontfamily="mono")
)