stacking alpha

stack-alpha.R

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Simple function to create a plot with N overlapping rectangles with 
# each having an alpha of 1/N
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
stack_alpha <- function(N) {
  plot_df <- tibble(
    x = seq(0.45, 0.55, length.out = N),
    y = seq(0.45, 0.55, length.out = N), 
    alpha = 1/N
  )
  
  ggplot(plot_df) + 
    geom_tile(aes(x, y, alpha = I(alpha)), fill = 'black', 
              width=0.5, height = 0.5, colour = NA) + 
    theme_bw()
}


stack_alpha(10)