R ggplot Changing color of one variable in stacked bar graph

Question

I have a data frame D that look like this:

Track <- c(0,0,0,-1,1,1)
Length <- c(1,1,2,1,3,1)
Legend <- c("A","B","A","C","B","C")
D <- data.frame(Track,Length,Legend)

D
# Track Length Legend
#     0      1      A
#     0      1      B
#     0      2      A
#    -1      1      C
#     1      3      B
#     1      1      C

I am currently using this code to plot it:

ggplot(Z, aes(x=Track, y=Length, fill=Legend)) +
      geom_bar(stat='identity') + geom_point() + expand_limits(x=0,y=0) + 
      theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank(), 
            panel.background = element_blank(), axis.line = element_line(colour = "black")) 

And the graph looks like this:

However I want to assign the color white to variable B. Is this manipulation possible? Additionally I am using dummy data for simplicity's sake in this post. The actual data that I will be using may have 10 or more different variables under Legend, so writing out each hex color doesn't look like a clean option.

Thank you for the help

Answer 1

Does this produce what you're after?

x <- length(levels(factor(Legend)))
x.colors <- hcl(h=seq(15,375,length=(x+1)),l=65,c=100)[1:x]
x.colors[x] <- "white"

ggplot(D, aes(x=Track, y=Length, fill=Legend)) +
  geom_bar(stat='identity',colour="black") + geom_point() + expand_limits(x=0,y=0) +
  scale_fill_manual(values=x.colors) +
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank(), 
        panel.background = element_blank(), axis.line = element_line(colour ="black"))

I added scale_fill_manual() assigning colors to A, B, and C. I also added colour="black" to geom_bar(). You could try it with and without the second part and see what you think.

Answer 2

You can use scale_fill_manual(values=c( .. and then your hex colors"

    ggplot(D, aes(x=Track, y=Length, fill=Legend)) +
      geom_bar(stat='identity') + scale_fill_manual(values=c("#000000","#FFFFFF", "#00FF00"))

Also can use

# The palette with grey:
cbPalette <- c("#999999", "#E69F00", "#56B4E9", "#009E73", "#F0E442", "#0072B2", "#D55E00", "#CC79A7")

# The palette with black:
cbbPalette <- c("#000000", "#E69F00", "#56B4E9", "#009E73", "#F0E442", "#0072B2", "#D55E00", "#CC79A7")

# To use for fills, add
  scale_fill_manual(values=cbPalette)

# Use a different gradient
    scale_colour_gradientn(colours=rainbow(4))

   # To use for line and point colors, add
      scale_colour_manual(values=cbPalette)