heatmapBarChart.R

install.packages("devtools")
require(devtools)
install_github("ramnathv/rCharts")
library(rCharts)

# Load the data file
data <- read.csv("citizenInitiatives_ch.csv", stringsAsFactors = F)

# Get only the year from each date (not an elegant solution here, better to use date)
data$year <- as.numeric(substr(data$date,1, 4))

# add the count of observations (votes) per year. The count starts at 0 each year
data <- do.call(rbind, by(data, data$year, function(dd) cbind(dd, n = as.numeric(0:(nrow(dd)-1)))))
rownames(data) <- NULL

# change the names of the data.frame to be highcharts-friendly
colnames(data) <- c('date', 'name', 'value', 'x', 'y')

### PLOT
a <- Highcharts$new()
a$chart(zoomType = "x", type = 'heatmap', width = 1000)
# Pass the data as JSON
a$series(name = "", data = rCharts::toJSONArray2(data, json = F, names = T))

# Define the color scale
a$addParams(colorAxis = list(min = 0, max = 100, stops = list(list(0, '#ab3d3f'),
	list(0.499, '#EED8D9'),list(0.5, '#ADC2C2'),list(1, '#336666'))))
a$yAxis(lineWidth = 0, minorGridLineWidth = 0, lineColor = 'transparent', title = list(text = ""),
	labels = list(enabled = FALSE), minorTickLength = 0, tickLength =  0, gridLineWidth =  0, minorGridLineWidth = 0)

a$addAssets(js = c("https://code.highcharts.com/modules/heatmap.js"))

# Customize the tooltip
formatter <- "#! function() { return '<div class=\"tooltip\" style=\"color:#686868;font-size:0.8em\">In <b>' +
	this.point.x + ',</b> the initiative:<br><br><i>' + this.point.name + '<br><br></i>gathered <b>' + this.point.value + '%</b> yes</div>'; } !#"
a$tooltip(formatter = formatter, useHTML = T, borderWidth = 2, backgroundColor = 'rgba(255,255,255,0.8)')
a

# Save the chart as HTML
a$save("heatmapBarChart.html")