Documentation feature request: Include examples in autoplot's documentation.

[ReeceGoding]

autoplot looks like great fun to play around with, but I see two major issues:

1. Little help for it seems to be easily available online
2. The documentation contains no examples whatsoever

I believe that adding some examples to its documentation would greatly improve it. At present, the user is largely left to guess what sort of inputs it will accept.

[yutannihilation]

I think this is a good idea, but the problem is that ggplot2 doesn't include any of the actual method implementation. So, I'm afraid this is difficult to do within ggplot2's document.

https://github.com/tidyverse/ggplot2/blob/21df8dc88e9b736a136bc39362defe2943008767/NAMESPACE#L17

[92amartins]

Maybe we could write a vignette describing the main use cases.

Happy to send a PR if that's the case.

[teunbrand]

I think a vignette might be overdoing it a bit, but it probably could get a separate docpage together with autolayer() and maybe fortify(). In the example section, you could simply implement dummy methods for a matrix or something, see below.

library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 4.3.1

mtx <- matrix(1:12, 3, 4)

# Matrix as tidy data
fortify.matrix <- function(model, ...) {
  dims <- dim(model)
  data.frame(
    row   = as.vector(.row(dims)),
    col   = as.vector(.col(dims)),
    value = as.vector(model)
  )
}

ggplot(mtx, aes(col, row, fill = value)) +
  geom_raster()

# Converting matrices to a raster layer
autolayer.matrix <- function(object, ...) {
  # We can use `data = object` here because we've defined a `fortify()`
  # method above
  geom_raster(aes(x = col, y = row, fill = value), data = object, ...)
}

ggplot() + autolayer(mtx)

# Converting matrices to a plot
autoplot.matrix <- function(object, ...) {
  ggplot(...) +
    autolayer(object) +
    # Adding a scale for the matrix
    scale_fill_viridis_c()
}

autoplot(mtx)

^{Created on 2023-09-25 with reprex v2.0.2}