I have the code below to generate the heatmap with annotation. ![enter image description here][1]

    library(pheatmap)
    # Generate some data
    test = matrix(rnorm(200), 20, 10)
    test[1:10, seq(1, 10, 2)] = test[1:10, seq(1, 10, 2)] + 3
    test[11:20, seq(2, 10, 2)] = test[11:20, seq(2, 10, 2)] + 2
    test[15:20, seq(2, 10, 2)] = test[15:20, seq(2, 10, 2)] + 4
    colnames(test) = paste("Test", 1:10, sep = "")
    rownames(test) = paste("Gene", 1:20, sep = "")
    # Add annotation as described above, and change the name of annotation
    annotation <- data.frame(Var1 = factor(1:10 %% 2 == 0, labels = c("Exp1", "Exp2")))
    rownames(annotation) <- colnames(test) # check out the row names of annotation
    pheatmap(test, annotation = annotation)


I'm wondering whether there is a way to add the labels in the annotation bar in R code. Thanks in advance. 
![enter image description here][2]


  [1]: https://s22.postimg.cc/6beg2ma81/Picture1.png
  [2]: https://s22.postimg.cc/z2b9su8dt/Picture2.png
use grid.text (part of base functions, earlier part of library "grid") (play with x and y coordinates): 

    pheatmap(test, annotation = annotation)
    grid.text(levels(annotation$Var1), x=c(0.25,0.6),y=c(0.89,0.89), gp=gpar(fontsize=10))

<a href="https://ibb.co/cxb6o9"><img src="https://preview.ibb.co/hMfXT9/Rplot01.png" alt="Rplot01" border="0"></a>