Add a knitr hook to automatically add tracker to plot

[mrjoh3]

in a knitr chunk that outputs a ggplot the chunk header could include track=tracker.object

tracker.object would point to a tracker defined earlier in the page

[mrjoh3]

I have had 2 attempts at this, first using the source hook

knit_hooks$set(
  source = function(x, options) {
    gg = eval(parse(text = x))
    print(class(gg))
    track <- options$ggtrack
    print(track)
    add_banner(gg, track)
  }
)

{r, ggtrack=track, eval=FALSE, results='hide'}

ggplot(mapping = aes(x = 1:10, y = rnorm(10))) +
  geom_bar(stat = 'identity') +
  theme_minimal() 

[mrjoh3]

second try was with

ggtrack_hook = function(before, options, envir) {
  if (before) {
    return()
  } else {
    class(envir$gg)
    add_banner(envir$gg, options$ggtrack)
  }
}

knitr::knit_hooks$set(ggtrack = track_hook)

[mrjoh3]

both are simple attempts, but the first one errored when adding the banner and the second seemed to work but the chart would not display.

both seemed to pass the correct objects into the hook, which was encouraging . But I spent too much time with little progress.

If anyone is interested see https://github.com/mrjoh3/ggtrack/blob/knitr-hook/R/knitr_hook.R https://github.com/mrjoh3/ggtrack/blob/knitr-hook/inst/working/hooks.Rmd