How to fill the background of a stat_poly_eq equation (ggpmisc) using ggplot2?

Question

Is there a way to fill the background of a stat_poly_eq equation ggpmisc with white color (or any other color) so that the black lines of the panel.grid are hidden?

# Data
df <- data.frame(x = c(1:100))
df$y <- 2 + 3 * df$x + rnorm(100, sd = 40)
df$yy <- 2 + 3 * df$x + 0.1 * df$x^2 + rnorm(100, sd = 40)

# Graph
library(ggplot2)
library(ggpmisc)

ggplot(data = df, aes(x = x, y = y)) +
  scale_x_continuous(limits = c(0,100), expand = c(0,0)) +
  scale_y_continuous(limits = c(0,400), expand = c(0,0)) +
  theme(panel.grid.major=element_line(colour="black",size=0.1)) +
  stat_poly_line() +
  stat_poly_eq(aes(
    label = paste(after_stat(eq.label),
                  after_stat(rr.label), sep = "*\", \"*")), size = 6, label.x = 0.07, label.y = 0.78) +
  geom_point()

Below is the graph as I would like:

Thanks for help

Answer 1

This could be achieved by switching the default geom used by stat_poly_eq to add the label. By default ggpp::geom_text_npc is used but there is also a geom_label_npc:

library(ggplot2)
library(ggpmisc)

ggplot(data = df, aes(x = x, y = y)) +
  scale_x_continuous(limits = c(0,100), expand = c(0,0)) +
  scale_y_continuous(limits = c(0,400), expand = c(0,0)) +
  theme(panel.grid.major=element_line(colour="black",size=0.1)) +
  stat_poly_line() +
  stat_poly_eq(aes(
    label = paste(after_stat(eq.label),
                  after_stat(rr.label), sep = "*\", \"*")), 
    size = 6, label.x = 0.07, label.y = 0.78, 
    geom = "label_npc", label.size = 0) +
  geom_point()