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WebGL Heatmaps in R

How to make webGL based heatmaps in R with Plotly.


New to Plotly?

Plotly is a free and open-source graphing library for R. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

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