Want individual components as subsets in a stacked bar chart - r

Question

I am trying to create a stacked bar plot which will show the revenue of the company and various components of its cost of sales (operating expenses. other fixed costs etc.). Now I want the individual components of the cost of sales to be shown on top of the revenue bar so that it is clear what part of the revenue is cost of sales.
Right now, I am only able to create a stacked bar plot which lays everything on top of each other. In other words, cost of sales is displayed on top of revenue.
Ideally, I would want the individual components of cost of sales to be displayed as subset of revenue.
Here's a brief look at the molten data frame I have:
Time variable value
2013-01-01 A 84.32153
2013-02-01 A 91.41203
2013-01-01 B 1214.29960
2013-02-01 B 1224.21256
2013-01-01 C 312.78462
2013-02-01 C 175.58130
2013-01-01 D 321.12000
2013-02-01 D 298.82000
In the above scenario, I want B to be displayed as the super set and A,C and D should be components of B for the two months shown above.
I am using the following code:
stackbar <- ggplot(temp, aes_string(x = 'Time',y='value', fill = "variable")) +
geom_bar(stat='identity') +
ylab("Count") + theme(legend.title = element_blank()) +
theme(legend.direction = "horizontal") +
theme(legend.position = c(1, 1)) +
theme(legend.justification = c(1, 0)) +
theme(panel.grid.minor.x=element_blank(),
panel.grid.minor.y=element_blank(), panel.background=element_blank(),
panel.grid.major.x=element_line(color='grey90',linetype='dashed'),
panel.grid.major.y=element_line(color='grey90',linetype='dashed')) +
theme(axis.ticks.x=element_blank()) + theme(axis.ticks.y=element_blank()) +
scale_colour_discrete(limits = levels(temp$variable))
Any help in this regard would be much appreciated.

Answer 1

What you want to do is to subset your data and have two geom_bar layers. First, you want to draw bars with variable B. Then, you draw the rest in the second geom_bar(). I hope this will give you the figure you want.
stackbar <- ggplot(mydf, aes(x = Time, y = value, fill = variable)) +
geom_bar(data = mydf[mydf$variable == "B",], stat = "identity") +
geom_bar(data = mydf[!mydf$variable == "B",], stat = "identity")+
ylab("Count") +
theme(legend.title = element_blank()) +
theme(legend.direction = "horizontal") +
theme(legend.position = c(1, 1)) +
theme(legend.justification = c(1, 0)) +
theme(panel.grid.minor.x=element_blank(),
panel.grid.minor.y=element_blank(), panel.background=element_blank(),
panel.grid.major.x=element_line(color='grey90',linetype='dashed'),
panel.grid.major.y=element_line(color='grey90',linetype='dashed')) +
theme(axis.ticks.x=element_blank()) + theme(axis.ticks.y=element_blank()) +
scale_colour_discrete(limits = levels(mydf$variable))
stackbar