Create a function in R to make all ggplot components more transparent

Question

I am looking for a function that makes my ggplot graphs more transparent. Setting up a new theme I believe that this is not all good, because, as my own documents say, "Use theme () to change individual components of the theme, allowing you to control the appearance of all components without plot data . '

Suppose we have this simple graph:

ggplot(economics) +
  aes(unemploy, psavert) +
  geom_point() +
  geom_smooth(se = F) +
  ggtitle('Unemploy vs Personal Savings Rate')

It will look like this:

My idea is to create a function that changes all the elements and makes them more transparent with some correlation, something like this:

make.invisible <- function(graph, alpha=.75){
  graph +
    # Change all elements
}

Is this possible with ggplot2?

Answer 1

, . edit_colors() colorblindr. ( : .)

p <- ggplot(economics) +
  aes(unemploy, psavert) +
  geom_point() +
  geom_smooth(se = F) +
  ggtitle('Unemploy vs Personal Savings Rate')

library(colorblindr) # devtools::install_github("clauswilke/colorblindr")
library(colorspace) # install.packages("colorspace", repos = "http://R-Forge.R-project.org") --- colorblindr requires the development version
# need also install cowplot; current version on CRAN is fine.

# modify alpha values using the alpha function from the scales package
p_alpha <- edit_colors(p, scales::alpha, alpha = .5)

# print
grid::grid.newpage()
grid::grid.draw(p_alpha)

alpha() , -, -. , , -, -:

mult_alpha <- function(color, alpha = .5) 
{
  col <- grDevices::col2rgb(color, TRUE)/255
  new_col <- grDevices::rgb(col[1, ], col[2, ], col[3, ], alpha*col[4, ])
  new_col[is.na(color)] <- NA
  new_col
}

p2 <- ggplot(iris, aes(Sepal.Length, fill = Species)) +
  geom_density(alpha = .3) + theme_bw()

p2_mult_alpha <- edit_colors(p2, mult_alpha, alpha = .7)

, , :

p2_alpha <- edit_colors(p2, scales::alpha, alpha = .7)

cowplot::plot_grid(p2_alpha, p2_mult_alpha)

( : alpha , : mult_alpha, ).

Answer 2

,

print(p, vp=viewport(gp=gpar(alpha=0.3)))