Failed to create Cairo backend!

[zh-zhang1984]

Hi, thanks for the excellent package; I encounter following error and am struggling to handle this issue; are there any hints for solving this problem?

> HeatMap_plot <- plot_heatmap(
+   dataset = Sepsis_seurat, 
+   markers = Allmarkers,n=2,
+   sort_var = c("Cell_Type","Condition"),
+   anno_var = c("Cell_Type","Condition","percent.mt","S.Score","G2M.Score"),
+   anno_colors = list(
+     "Set2",# RColorBrewer palette
+     c("red","orange","yellow","purple","blue","green"), # color vector
+                      "Reds",
+     c("blue","white","red"), # Three-color gradient
+     "Greens"))
Warning in set_colors(anno_colors[[i]], length(l)) :
  Number of colors required exceeds palette capacity. RdYlBu spectrum will be used instead.
`use_raster` is automatically set to TRUE for a matrix with more than
2000 columns You can control `use_raster` argument by explicitly
setting TRUE/FALSE to it.

Set `ht_opt$message = FALSE` to turn off this message.
Error in Cairo(width, height, type = "png", file = filename, pointsize = pointsize,  : 
  Failed to create Cairo backend!