WebGL Heatmaps in R

How to make webGL based heatmaps in R with Plotly.

Plotly Studio: Transform any dataset into an interactive data application in minutes with AI. Try Plotly Studio now.

WebGL Heatmap from an Image

library("jpeg")
library("plotly")

# Image processing
url <- "https://images.plot.ly/plotly-documentation/images/heatmap-galaxy.jpg"
tmpf <- tempfile()
download.file(url,tmpf,mode="wb")
data <- readJPEG(tmpf)
fr <- file.remove(tmpf) # remove the downloaded temp file

zdata = rowSums(data*255, dims = 2)

fig <- plot_ly(
            z = zdata,
            colorscale = list(c(0,0.5,1),c("blue", "white", "red")),
            type = "heatmapgl"
            )

fig

Reference

See https://plotly.com/r/reference/#heatmapgl for more information and options!

What About Dash?

Dash for R is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash for R at https://dashr.plot.ly/installation.

Everywhere in this page that you see fig, you can display the same figure in a Dash for R application by passing it to the figure argument of the Graph component from the built-in dashCoreComponents package like this:

library(plotly)

fig <- plot_ly() 
# fig <- fig %>% add_trace( ... )
# fig <- fig %>% layout( ... ) 

library(dash)
library(dashCoreComponents)
library(dashHtmlComponents)

app <- Dash$new()
app$layout(
    htmlDiv(
        list(
            dccGraph(figure=fig) 
        )
     )
)

app$run_server(debug=TRUE, dev_tools_hot_reload=FALSE)