Recompute after resizing about ggrepel

[hadley]

You're already doing the computation in the makeContent method. Maybe that is enough?

@pmur002 where's the best place to look for docs on grobs that redraw themselves as the plot changes size? Is there more to it than makeContent?

[slowkow]

In the makeContent method, I compute the line segment connecting the original data point to the text label. However, this method does not include computations to repel labels away from each other.

I guess what I might need is a makeContent or drawDetails method for the gTree that has all the textrepelgrob grobs. After a bit of hacking, no luck.

I tried something like this:

GeomTextRepel <- ggproto(...,
  draw_panel = function(...) {
    # 'grobs' is a list with many textrepelgrob's
    ggname("geom_text_repel", grobTree(children = grobs, cl = "textrepeltree"))
  }
)
# This doesn't seem to work...
drawDetails.textrepeltree <- function(x, recording) {
  # Repulsion computation should happen here,
  # where I should have access to all textrepelgrob children.
  print(x)
}
# This also doesn't seem to work...
makeContent.textrepeltree <- function(x) {
  # Repulsion computation should happen here,
  # where I should have access to all textrepelgrob children.
  print(x)
}

I'm now reading R Graphics, Second Edition by Paul Murrell, and it is helping me to understand how grid works, but I'm still a few steps away from seeing how this could be done. Chapter 8 is helpful, but does not have enough details on how to do calculations with a tree's children.

[hadley]

You might also need https://journal.r-project.org/archive/2013-2/murrell.pdf and https://www.stat.auckland.ac.nz/~paul/Reports/CustomGrobs/custom-grob.html

[slowkow]

Thanks for those additional links! It seems that makeContent is the proper function to use, and not drawDetails.

Following the examples, I expect that this function should be called upon resizing the plotting area. However, I'm not seeing any output.

# Never gets called :(
makeContent.textrepeltree <- function(x) {
  sink("/tmp/gridstuff.txt")
  cat("testing")
  sink()
  # cat(x$children[[1]]$name)
  x
}

If only I could get a makeContent function to be called that has access to all the textrepelgrob children, I would be on my way to getting this feature implemented.

[hadley]

Did you export the S3 method? It might be necessary because of the way the generic gets called.

[slowkow]

Thanks for the tip! After exporting, it works!

I'll post again when I've made more progress.

[slowkow]

@hadley It works! Thank you so much for the help.

[hadley]

Awesome!