Visualizing a custom color palette in R Studio

Question

I have what is probably the easiest question in the R Studio world. I'm and R novice, bumbling my way through a published program. The program generates dendrogram heatmaps, and I created a custom color palette for each of the dendrograms I need to export. My heatmaps look good, however, I don't know how to either (1) display the custom color-coded scale bar on my heatmap, or alternatively (2) just see and save the custom palette, as you can do with display.brewer.pal, which would allow me at least to have the palette so I can annotate later.

Here's what I have done

pal <- colorRampPalette(c("#4d4d4d", "white", "#32c200")) #GreytoGreen
curr.pal = pal(15)

which gives me (when I say View(curr.pal))

"#4D4D4D" "#666666" "#7F7F7F" "#999999" "#B2B2B2" "#CCCCCC" "#E5E5E5" "#FFFFFF" "#E1F6DA" "#C4EDB6" "#A7E491" "#89DC6D" "#6CD348" "#4FCA24" "#32C200"

The relevant part of the heatmap code is

myHeatmap <- function(x) {
   map.input = t(x)
   distance <- dist(map.input[, 18:24], method = "euclidean")
   cluster <- hclust(distance, method = "complete")
   heatmap(map.input, Rowv = as.dendrogram(cluster), Colv = NA, xlab = "Lag", col = curr.pal, scale = "none")

Any suggestions how to get the legend displayed for my 15 color palette on the heat map, or at least get a png of it? Thank you, I apologize for the easy question.

Answer 1

I tried to implement your code (at least, in a similar way) in "gplots" package. The heatmap.2 function has some extensions, as compared to heatmaps.

The code is attached (I used "mtcars" dataframe to play around):

library(gplots)
map.input <- scale(mtcars)
pal <- colorpanel(15, "#4d4d4d", "white", "#32c200") 
distance <- dist(map.input, method = "euclidean")
cluster <- hclust(distance, method = "complete")
heatmap.2(map.input, Rowv = as.dendrogram(cluster), Colv = TRUE, xlab = "Lag", col = pal, scale = "none", 
          trace = "none")

I can aslo easily export the png data in RStudio in the plot tab.