JFreeChart Dial chart in Coldfusion - coldfusion

Question

Has anyone an example of implementing a JFreechart Dial chart on Coldfusion?
Thanks

Answer 1

(This probably should not be a separate answer, but the other was already pretty long. So I am posting it separately to keep things organized and easy to find.)
In case you are looking for what jFreeChart calls a MeterChart, here is a quick and dirty example of that chart type.
MeterChart Code:
<cfscript>
// my chart settings
chartTitle = "My Meter Chart";
arrowValue = 55;
arrowUnits = "widgets";
chartWidth = 500;
chartHeight = 500;
// initialize meter ranges (LOW, MEDIUM, HIGH)
// note: quick and ugly code in dire need of improvement ...
low = createSolidMeterInterval("Low", 0, 40, createAwtColor(0, 255, 0, 120));
med = createSolidMeterInterval("Med", 40, 60, createAwtColor(255, 255, 0, 120));
high = createSolidMeterInterval("High", 60, 100, createAwtColor(255, 0, 0, 120));
// initialize arrow value
DefaultValueDataset = createObject("java", "org.jfree.data.general.DefaultValueDataset");
meterPointer = DefaultValueDataset.init(arrowValue);
//initialize plot and apply settings
plot = createObject("java", "org.jfree.chart.plot.MeterPlot").init();
plot.setDataset(meterPointer);
plot.setTickLabelsVisible(true);
plot.addInterval(low);
plot.addInterval(med);
plot.addInterval(high);
plot.setUnits(arrowUnits);
// create chart and convert it to an image
chart = createObject("java", "org.jfree.chart.JFreeChart").init(chartTitle, plot);
ChartUtilities = createObject("java", "org.jfree.chart.ChartUtilities");
ChartUtilities.applyCurrentTheme(chart);
// applyCurrentTheme seems to overwrite some settings, so we must reapply them
Color = createObject("java", "java.awt.Color");
plot.setBackgroundPaint(Color.GRAY);
plot.setNeedlePaint(Color.BLACK);
chartImage = chart.createBufferedImage(chartWidth, chartHeight);
ImageFormat = createObject("java", "org.jfree.chart.encoders.ImageFormat");
EncoderUtil = createObject("java", "org.jfree.chart.encoders.EncoderUtil");
bytes = EncoderUtil.encode( chartImage, ImageFormat.PNG);
</cfscript>
<!--- display in browser --->
<cfcontent type="image/png" variable="#bytes#">
Auxiliary functions:
<cfscript>
// quick and ugly functions. could be improved ...
function createSolidMeterInterval(Title, fromValue, toValue, BgColor) {
var Range = createObject("java", "org.jfree.data.Range").init(arguments.fromValue, arguments.toValue);
var MeterInterval = createObject("java", "org.jfree.chart.plot.MeterInterval");
return MeterInterval.init(arguments.Title, Range // interval from / to range
, javacast("null", "") // outline color
, javacast("null", "") // outline stroke
, arguments.BgColor // background color
);
}
// using java.awt.Color is a pain due to all the javacasts ...
function createAwtColor(r, g, b, alpha) {
var color = createObject("java", "java.awt.Color");
return color.init( javacast("int", arguments.r)
, javacast("int", arguments.g)
, javacast("int", arguments.b)
, javacast("int", arguments.alpha) // transparency
);
}
</cfscript>

Answer 2

The package org.jfree.chart.demo has examples of how to construct a few basic charts; click on the class name to see the source. The methods of org.jfree.chart.ChartFactory show how to construct still more. The class org.jfree.chart.ChartUtilities includes methods to stream charts in several formats. A corresponding response.setContentType() works from any servlet container.
If this is terra incognita, I'd recommend The JFreeChart Developer Guide†.
†Disclaimer: Not affiliated with Object Refinery Limited; just a satisfied customer and very minor contributor.

Answer 3

Using trashgod's suggestions, I created a very rudimentary example for CF7. You can obviously do much more with it. Just review the api and/or purchase the developer guide.
Install:
Download latest jfreeChart. Copy the following jars into {cf_root}\WEB-INF\lib and restart CF. Note, jar version numbers may vary.
jfreechart-1.0.13.jar
jcommon-1.0.16.jar
Sample:
<cfscript>
// my chart settings
chartTitle = "My Dial Chart";
arrowValue = 55;
dialMinimum = 0;
dialMaximum = 100;
chartWidth = 500;
chartHeight = 500;
// initialize basic components of the chart
// see jFreeChart API on how to customize the components settings further
DefaultValueDataset = createObject("java", "org.jfree.data.general.DefaultValueDataset");
pointerValue = DefaultValueDataset.init(arrowValue);
dialPointer = createObject("java", "org.jfree.chart.plot.dial.DialPointer$Pointer").init();
dialFrame = createObject("java", "org.jfree.chart.plot.dial.StandardDialFrame").init();
dialBackground = createObject("java", "org.jfree.chart.plot.dial.DialBackground").init();
// tweak the default range to make it more appealing.
// see angle/extent: http://java.sun.com/developer/technicalArticles/GUI/java2d/java2dpart1.html
dialScale = createObject("java", "org.jfree.chart.plot.dial.StandardDialScale").init();
dialScale.setLowerBound(dialMinimum);
dialScale.setUpperBound(dialMaximum);
dialScale.setStartAngle(-150);
dialScale.setExtent(-240);
//initialize plot and apply settings
plot = createObject("java", "org.jfree.chart.plot.dial.DialPlot").init();
plot.setDialFrame(dialFrame);
plot.setBackground(dialBackground);
plot.setDataset(pointerValue);
plot.addScale(0, dialScale);
plot.addPointer(dialPointer);
// create chart and convert it to an image
chart = createObject("java", "org.jfree.chart.JFreeChart").init(chartTitle, plot);
chartImage = chart.createBufferedImage(chartWidth, chartHeight);
ImageFormat = createObject("java", "org.jfree.chart.encoders.ImageFormat");
EncoderUtil = createObject("java", "org.jfree.chart.encoders.EncoderUtil");
bytes = EncoderUtil.encode( chartImage, ImageFormat.PNG);
</cfscript>
<!--- display in browser --->
<cfcontent type="image/png" variable="#bytes#">