WebGL Text and Annotations in R

How to add WebGL text labels and annotations to plots in R.

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Heatmap with Annotations

library(plotly)
library(random)

n=250
t=12
x = c(rep(0:(n-1), times=t))
y = c(rep(0:(t-1), each=n))
z = randomNumbers(n=n*t, min=1, max=10, col=n)
text = c(replicate(t*n, sample(c("A","T","G","C"), 1)))

steps = list()
for (e in c(0:(n-30))){
  step <-  list(
    list(
      args = list('xaxis.range', c(-0.5 + e, 30.5 + e)),
      method = "relayout",
      label = e,
      value = e
    )
  )
  steps[e] <- step
}

fig <- plot_ly() 
fig <- fig %>%
  add_trace(
    type='heatmap',
    z = z
  ) 
fig <- fig %>%
  add_trace(
    mode = "text",
    text = text,
    type = "scattergl",
    textfont = list(
      size = 20
    ),
    x = x,
    y = y
  ) 
fig <- fig %>%
  layout(
    xaxis = list(
      range = c(-0.5, 30.5),
      showline = F,
      zeroline = F,
      showgrid = F
    ),
    yaxis = list(
      showline = F,
      zeroline = F,
      showgrid = F
    ),
    sliders=list(
      list(
        active = 0,
        steps = steps
      )
    )
  )

fig

Reference

See https://plotly.com/r/reference/#scattergl for more information and chart attribute 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)