theme_nothing(base_size = 12, legend = FALSE)

# no legend example
n <- 50
df <- expand.grid(x = 1:n,y = 1:n)[sample(n^2,.5*n^2),]
p <- ggplot(df, aes(x, y)) + geom_raster()
p
p + theme_nothing()
p + theme_nothing(legend = TRUE) # no difference
p +
  scale_x_continuous(expand = c(0,0)) +
  scale_y_continuous(expand = c(0,0)) +
  theme_nothing()



# legend example
df$class <- factor(sample(0:1, .5*n^2,  replace = TRUE))
p <- ggplot(df, aes(x, y)) + geom_raster(aes(fill = class))
p
p + theme_nothing()
p + theme_nothing(legend = TRUE)

p <- p +
  scale_x_continuous(expand = c(0,0)) +
  scale_y_continuous(expand = c(0,0))
p
p + theme_nothing()
p + theme_nothing(legend = TRUE)