可视化 R 中的颜色/调色板列表

Question

I have following data.frame with rgb values. Hence each row indicates a color.

> ddf
       r     g     b
1  0.374 0.183 0.528
2  0.374 0.905 0.337
3  0.051 0.662 0.028
4  0.096 0.706 0.898
5  0.876 0.461 0.628
6  0.415 0.845 0.286
7  0.596 0.070 0.523
8  0.724 0.101 0.673
9  0.847 0.434 0.937
10 0.588 0.885 0.604
11 0.481 0.366 0.337
12 0.142 0.075 0.276
13 0.819 0.737 0.658
14 0.910 0.722 0.979
15 0.969 0.012 0.451
16 0.887 0.536 0.123
17 0.432 0.967 0.446
18 0.927 0.125 0.332
19 0.381 0.646 0.656
20 0.040 0.898 0.798
> 
> dput(ddf)
structure(list(r = c(0.374, 0.374, 0.051, 0.096, 0.876, 0.415, 
0.596, 0.724, 0.847, 0.588, 0.481, 0.142, 0.819, 0.91, 0.969, 
0.887, 0.432, 0.927, 0.381, 0.04), g = c(0.183, 0.905, 0.662, 
0.706, 0.461, 0.845, 0.07, 0.101, 0.434, 0.885, 0.366, 0.075, 
0.737, 0.722, 0.012, 0.536, 0.967, 0.125, 0.646, 0.898), b = c(0.528, 
0.337, 0.028, 0.898, 0.628, 0.286, 0.523, 0.673, 0.937, 0.604, 
0.337, 0.276, 0.658, 0.979, 0.451, 0.123, 0.446, 0.332, 0.656, 
0.798)), .Names = c("r", "g", "b"), class = "data.frame", row.names = c(NA, 
-20L))

How can I visualize these colors? This can be either as bars of color or a palette or a pie chart. I tried to use following method but could not fit it in my data:

pie(rep(1,20), col=rainbow(20)) 

Answer 1

I think the simplest option is scales. This also has the advantage of showing the hex values in the colours.

library(scales)
pal <- rgb(ddf$r, ddf$g, ddf$b)
show_col(pal)

Answer 2

image() will work well here if you convert the colors via rgb()

image(1:nrow(ddf), 1, as.matrix(1:nrow(ddf)), 
      col=rgb(ddf$r, ddf$g, ddf$b),
      xlab="", ylab = "", xaxt = "n", yaxt = "n", bty = "n")

Answer 3

As an alternative to the solution using image you could also use polygon and create a quite similar plot:

plot(NA, xlim=c(0, nrow(ddf)), ylim=c(0,1))

for (i in 1:nrow(ddf)) {

  row <- ddf[i,]
  color <- rgb(red=row$r, green=row$g, blue=row$b)
  polygon(x=c(i-1, i, i, i-1), y=c(0, 0, 1, 1), col = color)
}

Answer 4

You could also use ggplot2 :

library(ggplot2)
qplot(x=1:nrow(ddf), y = 1, fill=factor(1:nrow(ddf)), geom="tile") +
  scale_fill_manual(values = rgb(ddf$r, ddf$g, ddf$b)) +
  theme_void()+
  theme(legend.position="none")