ggplot2: extract data for points along lines

Question

I'm trying to extract xy coordinates for points along a curved line in a ggplot. ggplot_build() shows some of the data, but it still only contains the start and end coordinates of the curve. Is there any way to get at the intermediate points?

Edit: Example code using geom_curve() .

ggplot(df, aes(x = x, y = y, xend = xend, yend=yend)) + geom_curve(curvature = .4)

Answer 1

Here's my best attempt, given the info you've supplied. If you could provide a reproducible example, perhaps a better solution could be supplied.

p <- ggplot(mpg, aes(cty, hwy)) +
  geom_smooth()
x_coords <- ggplot_build(p)$data[[1]]$x
y_coords <- ggplot_build(p)$data[[1]]$y

p

plot(x_coords, y_coords, type = "l")