library(ggplot2)
library(geomtextpath) # using cran v0.1.1
ggplot(data.frame(a = 1:2)) +
geom_line(aes(x = a, y = a), colour = '#00000022') +
geom_textline(aes(x = a, y = a + 0.2, label = "geomtextline"), colour = '#00000022')
# same for linecolour and textcolour