ggproto_text.R

In ELICHOS/dataviz:

GeomSimplePoint <- ggproto("GeomNewText", Geom,
                           required_aes = c("x", "y", "label"),
                           default_aes = aes(colour = "black"),
                           draw_key = draw_key_text,
                           
                           draw_panel = function(data, panel_params, coord) {
                             coords <- coord$transform(data, panel_params)
                             grid::textGrob(label = 
                               coords$x, coords$y,
                               pch = coords$shape,
                               gp = grid::gpar(col = coords$colour)
                             )
                           }
)

geom_simple_point <- function(mapping = NULL, data = NULL, stat = "identity",
                              position = "identity", na.rm = FALSE, show.legend = NA, 
                              inherit.aes = TRUE, ...) {
  layer(
    geom = GeomSimplePoint, mapping = mapping,  data = data, stat = stat, 
    position = position, show.legend = show.legend, inherit.aes = inherit.aes,
    params = list(na.rm = na.rm, ...)
  )
}

ggplot(mpg, aes(displ, hwy)) + 
  geom_simple_point()