Inspired by how easy it was to get JFreeChart working and some code from former colleague Andrew Bruno, I thought it’d be nice to write some JRuby to generate Edward Tufte’s Sparklines.
Here’s some simple example code on a semi-random dataset:
# Mostly inspired by # http://left.subtree.org/2007/01/15/creating-sparklines-with-jfreechart/ # have JFreeChart in your classpath, obviously, as well as jcommon.jar require 'java' module Graph class Sparkline include_class 'java.io.File' include_class 'org.jfree.chart.ChartUtilities' include_class 'org.jfree.chart.JFreeChart' include_class 'org.jfree.chart.axis.NumberAxis' include_class 'org.jfree.chart.plot.XYPlot' include_class 'org.jfree.chart.renderer.xy.StandardXYItemRenderer' include_class 'org.jfree.data.xy.XYSeries' include_class 'org.jfree.data.xy.XYSeriesCollection' include_class 'org.jfree.chart.plot.PlotOrientation' def initialize(width=200, height=80, data=[]) @width = width @height = height dataset = create_sample_data() if data.empty? @chart = create_chart(dataset) end def render_to_file(filename, format="png") javafile = java.io.File.new(filename) ChartUtilities.saveChartAsPNG(javafile, @chart, @width, @height) end private def create_sample_data series = XYSeries.new("Sparkline") data = [20] (1..99).each {|x| y = (data.last + (rand(x) + 1)) / 2 data << y series.add(x, y) } dataset = XYSeriesCollection.new dataset.addSeries(series) return dataset end def create_chart(dataset) x = NumberAxis.new x.setTickLabelsVisible(false) x.setTickMarksVisible(false) x.setAxisLineVisible(false) x.setNegativeArrowVisible(false) x.setPositiveArrowVisible(false) x.setVisible(false) y = NumberAxis.new y.setTickLabelsVisible(false) y.setTickMarksVisible(false) y.setAxisLineVisible(false) y.setNegativeArrowVisible(false) y.setPositiveArrowVisible(false) y.setVisible(false) plot = XYPlot.new plot.setDataset(dataset) plot.setDomainAxis(x) plot.setDomainGridlinesVisible(false) plot.setDomainCrosshairVisible(false) plot.setRangeGridlinesVisible(false) plot.setRangeCrosshairVisible(false) plot.setRangeAxis(y) plot.setOutlinePaint(nil) plot.setRenderer(StandardXYItemRenderer.new(StandardXYItemRenderer::LINES)) chart = JFreeChart.new(nil, JFreeChart::DEFAULT_TITLE_FONT, plot, false) chart.setBorderVisible(false); return chart end end # class Sparkline end # class Graph sp = Graph::Sparkline.new puts "Rendering sparkline" sp.render_to_file("sparkline.png")
And the resulting sparkline chart:
Code: http://kfahlgren.com/code/sparkline.jrb
UPDATE: Removed some of the useless sample generation code
Have you done anything with DefaultCategoryDatasets? I’m trying to build some stacked bar charts in JRuby and your code is excellent but I can’t seem to make things work with other types of datasets, grrrrr. But then again, my Ruby isn’t exactly sharp.
The following chunk of code is what I need to port over…
DefaultCategoryDataset result = new DefaultCategoryDataset();
result.addValue(0, “Closed”, “”);
result.addValue(0, “InVerfication”, “”);
result.addValue(0, “Delivered”, “”);
result.addValue(0, “On-hold”, “”);
result.addValue(0, “In-work”, “”);
result.addValue(0, “Rejected”, “”);
result.addValue(0, “Duplicate”, “”);
result.addValue(0, “Assigned”, “”);
result.addValue(0, “Submitted”, “”);
mdweezer:
I haven’t the foggiest idea what you’re actually trying to do, but:
# Mostly inspired by http://left.subtree.org/2007/01/15/creating-sparklines-with-jfreechart/ # have JFreeChart in your classpath, obviously, as well as jcommon.jar require 'java' module Graph class Sparkline include_class 'java.io.File' include_class 'org.jfree.chart.ChartUtilities' include_class 'org.jfree.chart.JFreeChart' include_class 'org.jfree.data.category.DefaultCategoryDataset' include_class 'org.jfree.chart.ChartFactory' include_class 'org.jfree.chart.plot.PlotOrientation' def initialize(width=200, height=80, data=[]) @width = width @height = height dataset = create_sample_data() if data.empty? @chart = create_chart(dataset) end def render_to_file(filename, format="png") javafile = java.io.File.new(filename) ChartUtilities.saveChartAsPNG(javafile, @chart, @width, @height) end private def create_sample_data dataset = DefaultCategoryDataset.new dataset.addValue(1, "Closed", "") dataset.addValue(1, "InVerfication", "") dataset.addValue(2, "Delivered", "") dataset.addValue(2, "On-hold", "") dataset.addValue(3, "In-work", "") dataset.addValue(3, "Rejected", "") dataset.addValue(3, "Duplicate", "") dataset.addValue(3, "Assigned", "") dataset.addValue(4, "Submitted", "") return dataset end def create_chart(dataset) chart = ChartFactory.createWaterfallChart("Phase","Name", "", dataset, PlotOrientation::VERTICAL, true, true, false) return chart end end # class Sparkline end # class Graph sp = Graph::Sparkline.new puts "Rendering sparkline" sp.render_to_file("sparkline.png")Keith,
I appreciate the response, I kept getting “addValue” incorrect method errors… I’m building stacked bar charts with the data. I’m using data scraped from a database, I just used those values to figure out how to actually add data to the dataset. Not quite sure what I was doing wrong but I”ll see what I can do. Again, I appreciate it, thanks!
What’s the actual error you’re getting/can you post more of the code you’re using?
Hope this helps
Would you be so kind as to help our a Ruby/Java noob? Say I just created a default, blank rails app in my jRuby install. I have the jfreechart and jcommon JARs in my classpath. What all do I have to do to get your code to work and start producing charts. I don’t know Ruby (nor the MVC framework), I don’t know Java, and I most certainly don’t know how Java works with jRuby. I would like to learn, but since I learn by example, and most examples on the net are very incomplete, I’m having a hard time. Could you provide any assistance?
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