Rcharts nPlot() Percentages with discrete/multiBarChart

I want to use the nPlot() function in RCharts to plot percentages of people falling into discrete groups, rather than frequencies.

For example: Using the HairEyeColor data/code below I am able to consider the percentage of people with different hair colors (my grouping variable), as a function of their eye color.

## server.r
library(rCharts)
library(shiny)
library(reshape)

HairEyeColor1 <- melt(round(prop.table(HairEyeColor[,,1],2)*100,2))
names(HairEyeColor1) <- c("Hair", "Eye", "Percent")

shinyServer(function(input, output) {
output$myChart <- renderChart({
p1 <- nPlot(Percent ~ Eye, group = "Hair", data = HairEyeColor1, type = multiBarChart")
p1$addParams(dom = 'myChart')
return(p1)
})
})

## ui.R
library(rCharts)
library(shiny)

shinyUI(pageWithSidebar(
headerPanel("rCharts: Interactive Charts from R using NVD3.js"),
sidebarPanel(
wellPanel(
    helpText(   "Look at the pretty graph"
    )
    ),
wellPanel(
    helpText(   "Look at the pretty graph"
    )
    ),
wellPanel(
    helpText(   "Look at the pretty graph"
    )
    )
),
mainPanel(
div(class='wrapper',
tags$style(".Nvd3{ height: 400px;}"),
showOutput("myChart","Nvd3")
)
)
))

Say I just wanted to look at a single factor, like Hair. Is there a way to plot their percentages using nPlot()?

prop.table(rowSums(HairEyeColor[,,1]))
    Black     Brown       Red       Blond 
    0.2007168 0.5125448   0.1218638 0.1648746

With type=multiBarChart I have tried:

p1 <- nPlot(Percent ~ , group = "Hair", data = HairEyeColor1, type = multiBarChart")

This fails entirely. I have also tried:

p1 <- nPlot(Percent ~ 1, group = "Hair", data = HairEyeColor1, type = multiBarChart")

This at least passes some graph to Shiny UI. But this looks hideous and functionality (appearance of X/Y-axis, clicking on graph) is all lost.

I thought this would be appropriate for nPlot(type=discreteBarChart) but the data layout for this seems to want a dataframe with a single factor variable. So I can't quite see how to trick nPlot(type=discreteBarChart) into taking a vector of proportions/percentages.

Any suggestions appreciated.

Solution

Here is how to do it with nPlot. You can see the resulting plot here. If you want to stack the bars by default, add the line n1$chart(stacked = TRUE) before you print the chart.

# prepare data
require(plyr)
dat = as.data.frame(HairEyeColor)
dat = ddply(dat, .(Hair), summarize, Freq = sum(Freq), Group = "A")

# draw chart
require(rCharts)
n1 <- nPlot(Freq ~ Group, data = dat, group = 'Hair', type = 'multiBarChart')
n1