scale_fill_gradientn() - alpha value

[Jakub_Komarek]

Hi,

how could I set an aplha value when I'm using scale_fill_gradientn()?

Thank you!

[nirgrahamuk]

@Jakub_Komarek

scale_fill_gradientn

library(tidyverse)

ggplot(faithfuld, aes(waiting, eruptions)) +
  geom_raster(aes(fill = density)) +
  scale_fill_gradientn(colours = terrain.colors(10,alpha=0.5))

[Z3tt]

... or simply this way, no matter which scale_fill_* or scale_color_* function you use:

library(tidyverse)

ggplot(faithfuld, aes(waiting, eruptions)) +
  geom_raster(aes(fill = density), alpha = 0.5) +
  scale_fill_gradientn(colours = terrain.colors(10))

If you want to have changing alpha values, you map to it inside the aes as you do with any other aesthetic: geom_tile(aes(fill = density, alpha = x).