Multi-Bar Chart

This example demonstrates a multi-bar chart, in which bars are clustered. It also demonstrates using alternative plot area background colors, and putting legends internal to the plot area.

A multi-bar chart is a bar chart in which multiple data sets are represented by drawing the bars side by side in a cluster. The multi-bar layer is created by using XYChart.addBarLayer2 with the Side predefined constant.

In this example, the two alternative background colors in the plot area is achieved by specifying two background colors in PlotArea.setBackground. ChartDirector also supports another method PlotArea.setAltBgColor that can be used for both horizontal and vertical alternative background colors.

Note that in this example, a margin is configured at the top of the plot area for the legend keys. This is achieved by using Axis.setMargin.

[File: cfdemo/multibar.cfm]

<cfscript>

// ChartDirector for ColdFusion API Access Point
cd = CreateObject("java", "ChartDirector.CFChart");

// A utility to allow us to create arrays with data in one line of code
function Array() {
    var result = ArrayNew(1);
    var i = 0;
    for (i = 1; i LTE ArrayLen(arguments); i = i + 1)
        result[i] = arguments[i];
    return result;
}

// The data for the bar chart
data0 = Array(100, 125, 245, 147, 67);
data1 = Array(85, 156, 179, 211, 123);
data2 = Array(97, 87, 56, 267, 157);
labels = Array("Mon", "Tue", "Wed", "Thu", "Fri");

// Create a XYChart object of size 400 x 240 pixels
c = cd.XYChart(400, 240);

// Add a title to the chart using 10 pt Arial font
c.addTitle("         Average Weekday Network Load", "", 10);

// Set the plot area at (50, 25) and of size 320 x 180. Use two alternative background colors
// (0xffffc0 and 0xffffe0)
c.setPlotArea(50, 25, 320, 180, "0xffffc0", "0xffffe0");

// Add a legend box at (55, 18) using horizontal layout. Use 8 pt Arial font, with transparent
// background
c.addLegend(55, 18, False, "", 8).setBackground(cd.Transparent);

// Add a title to the y-axis
c.yAxis().setTitle("Throughput (MBytes Per Hour)");

// Reserve 20 pixels at the top of the y-axis for the legend box
c.yAxis().setTopMargin(20);

// Set the x axis labels
c.xAxis().setLabels(labels);

// Add a multi-bar layer with 3 data sets and 3 pixels 3D depth
layer = c.addBarLayer2(cd.Side, 3);
layer.addDataSet(data0, "0xff8080", "Server ##1");
layer.addDataSet(data1, "0x80ff80", "Server ##2");
layer.addDataSet(data2, "0x8080ff", "Server ##3");

// Output the chart
chart1URL = c.makeSession(GetPageContext(), "chart1");

// Include tool tip for the chart
imageMap1 = c.getHTMLImageMap("", "", "title='{dataSetName} on {xLabel}: {value} MBytes/hour'");

</cfscript>
<html>
<body style="margin:5px 0px 0px 5px">
<div style="font-size:18pt; font-family:verdana; font-weight:bold">
    Multi-Bar Chart
</div>
<hr style="border:solid 1px #000080" />
<cfoutput>
<div style="font-size:9pt; font-family:verdana; margin-bottom:1.5em">
    <a href='viewsource.cfm?file=#CGI.SCRIPT_NAME#'>View Source Code</a>
</div>
<img src="getchart.cfm?#chart1URL#" usemap="##map1" border="0" />
<map name="map1">#imageMap1#</map>
</cfoutput>
</body>
</html>