Using discrete custom color in a plotly heatmap

Question

I\'m trying to generate a plotly heatmap, where I\'d like the colors to be specified by a discrete scale.

Here\'s what I mean:

Gene

Answer 1

A nice way for creating discrete color breaks is given in question 59516054 . Given the offered Z_Breaks function, you can center the colorbar tick labels in the middle of each box by using the function:

tickpos <- function(nFactor) {
    pos <- unique((head(Z_Breaks(nFactor), -1)) + head(Z_Breaks(nFactor))[2] / 2) * (nFactor - 1)
}

and then assigning it to the tickval argument of colorbar:

colorbar <- list(tickvals = tickpos(nFactor), ticktext = names(colours))