WebGL Heatmaps in R

How to make webGL based heatmaps in R with Plotly.

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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