报错信息：
Error in grDevices::pdf(file = filename, ..., version = version) :
invalid font type
In addition: Warning messages:
1: In grDevices::pdf(file = filename, ..., version = version) :
font family 'Helvetica' not found in PostScript font database
2: In grDevices::pdf(file = filename, ..., version = version) :
font family 'Helvetica' not found in PostScript font database

报错情况与代码

WGCNA进行模块的GO富集作图时报错

###前面省略
  load(file = 'step1_input.Rdata')
  load(file = "step2_beta_value.Rdata")
  load(file = "step3_genes_modules.Rdata")
  load(file = "step4_design.Rdata")
  
  table(moduleColors)
  group_g <- data.frame(gene=colnames(datExpr),
                        group=moduleColors)
  write.csv(group_g,file = "gene_moduleColors.csv",row.names = F, quote = F) ## 导出了对应模块所有基因
  
  # 选择mouse的基因组进行注释及ID转化啥的，如果是人的，另有R包
  library(clusterProfiler)
  library(org.Mm.eg.db)
  library(org.Hs.eg.db)
  tmp <- bitr(group_g$gene,fromType = genetype,  # "SYMBOL"   "ENSEMBL"
              toType = "ENTREZID",
              OrgDb = OrgDb )
  de_gene_cluster <- merge(tmp,group_g, by.x=genetype, by.y="gene")
  table(de_gene_cluster$group)
  
  ###run go analysis
  formula_res <- compareCluster(
    ENTREZID~group,
    data = de_gene_cluster,
    fun = "enrichGO",
    OrgDb = OrgDb,
    ont = "BP",  #One of "BP", "MF", and "CC"  or "ALL"
    pAdjustMethod = "BH",
    pvalueCutoff = 0.05,
    qvalueCutoff = 0.25
  )
  
  lineage1_ego <- simplify( 
    formula_res,
    cutoff=0.5,
    by="p.adjust",
    select_fun=min
  )
  save(group_g,formula_res,lineage1_ego,file="step5_GOananlysis.Rdata")
  #出图
  dotp <- dotplot(lineage1_ego,
                  showCategory=10,
                  label_format=90)
  ggsave(dotp,filename= "step5_modul_GO_term.pdf", width = 1.2*ncol(MEs), height = 2*ncol(MEs))

信息查找与报错排查

r - Error when exporting ggplot graphs to pdf: invalid font type - Stack Overflow

最终解决办法

添加device = cairo_pdf，能存图了，但还是有warning，之后若还报错再去研究怎么安装字体吧