flatten.R

flatten_points <- function(plot, width = 10, height = 5, dpi = 200) {
  is_geom_point <- sapply(plot$layers, function(layer) {
    "GeomPoint" %in% class(layer$geom)
  })

  plot_flat   <- plot + ggplot2::theme_void()
  plot_vector <- plot

  plot_flat$layers   <- plot$layers[is_geom_point]
  plot_vector$layers <- plot$layers[!is_geom_point]

  filename <- tempfile(fileext = ".png")

  ggplot2::ggsave(
    filename = filename,
    plot     = plot_flat,
    device   = "png"
    # units    = "in",
    # width    = width,
    # height   = height,
    # dpi      = dpi
  )

  img <- png::readPNG(filename)
  unlink(filename)

  built <- ggplot2::ggplot_build(plot = plot_vector)
  range.values <- c(
    built$layout$panel_params[[1]]$x.range,
    built$layout$panel_params[[1]]$y.range
  )

  plot_vector +
    ggplot2::annotation_raster(
      img,
      xmin = range.values[1],
      xmax = range.values[2],
      ymin = range.values[3],
      ymax = range.values[4]
    )
}

library(ggplot2)
d <- data.frame(
  x = rnorm(n = 1000),
  y = rnorm(n = 1000)
)

p <- ggplot(d, aes(x, y)) +
  geom_point()

flatten_points(p, width = 5, height = 4, dpi = 300)

ggsave(
  plot = flatten_points(p, width = 5, height = 3),
  filename = "temp.svg",
  width = 10,
  height = 5
)