Change pheatmap plot background colour

Question

Is there a way I can change the plot background of pheatmap plot in R from white to let say black

library(pheatmap)
# Create test matrix
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 = "")
# Draw heatmapspheatmap(test)
pheatmap(test)

I tried, but it was not succesful

 pheatmap(test , bg="black")

Or is there a way to combine pheatmap with ggplot2 function of theme(plot.background = element_rect(colour = 'black', fill = 'black'))

Answer 1

You can change the colors of grobs in the object generate by pheatmap:

p <- pheatmap(test)

library(grid)
# Set white color for dendrogram lines and for text
for (k in c(1,2,4,5)) {
  p$gtable$grobs[[k]]$gp <- gpar(col="white")
}
p$gtable$grobs[[6]]$children[[2]]$gp <- gpar(col="white", fontsize=10)
# Draw a black box behind the heatmap as background
grid.draw(rectGrob(gp=gpar(fill="black", lwd=0)))
# Draw the heatmap
grid.draw(p)

Edit. As suggested by @Keniajin, a shorter solution is:

grid.draw(rectGrob(gp=gpar(fill="black", lwd=0)))
grid.draw(p)
grid.gedit("layout", gp = gpar(col = "white", text = ""))