ChartDirector 6.1 (Java Edition)

Custom Clickable Objects




In this example, a clickable line chart will be created with legend keys, a title box, a vertical mark with label, and a custom text box. All these objects will be clickable in addition to the lines and the data points.

This example also demonstrate how to use client side Javascript as the click handler.

The code for this example is listed below.

[JSP Version] jspdemo/customclick.jsp
<%@page import="ChartDirector.*" %>
<%
// The data for the line chart
double[] data0 = {50, 55, 47, 36, 42, 49, 63, 62, 73, 59, 56, 50, 64, 60, 67, 67, 58, 59, 73, 77,
    84, 82, 80, 84};
double[] data1 = {36, 28, 25, 33, 38, 20, 22, 30, 25, 33, 30, 24, 28, 36, 30, 45, 46, 42, 48, 45,
    43, 52, 64, 70};

// The labels for the line chart
String[] labels = {"Jan-04", "Feb-04", "Mar-04", "Apr-04", "May-04", "Jun-04", "Jul-04", "Aug-04",
    "Sep-04", "Oct-04", "Nov-04", "Dec-04", "Jan-05", "Feb-05", "Mar-05", "Apr-05", "May-05",
    "Jun-05", "Jul-05", "Aug-05", "Sep-05", "Oct-05", "Nov-05", "Dec-05"};

// Create an XYChart object of size 600 x 360 pixels, with a light blue (EEEEFF) background, black
// border, 1 pxiel 3D border effect and rounded corners
XYChart c = new XYChart(600, 360, 0xeeeeff, 0x000000, 1);
c.setRoundedFrame();

// Set plotarea at (55, 60) with size of 520 x 240 pixels. Use white (ffffff) as background and grey
// (cccccc) for grid lines
c.setPlotArea(55, 60, 520, 240, 0xffffff, -1, -1, 0xcccccc, 0xcccccc);

// Add a legend box at (55, 58) (top of plot area) using 9pt Arial Bold font with horizontal layout
// Set border and background colors of the legend box to Transparent
LegendBox legendBox = c.addLegend(55, 58, false, "Arial Bold", 9);
legendBox.setBackground(Chart.Transparent);

// Reserve 10% margin at the top of the plot area during auto-scaling to leave space for the
// legends.
c.yAxis().setAutoScale(0.1);

// Add a title to the chart using 15pt Times Bold Italic font. The text is white (ffffff) on a blue
// (0000cc) background, with glass effect.
ChartDirector.TextBox title = c.addTitle("Monthly Revenue for Year 2000/2001",
    "Times New Roman Bold Italic", 15, 0xffffff);
title.setBackground(0x0000cc, 0x000000, Chart.glassEffect(Chart.ReducedGlare));

// Add a title to the y axis
c.yAxis().setTitle("Month Revenue (USD millions)");

// Set the labels on the x axis. Draw the labels vertical (angle = 90)
c.xAxis().setLabels(labels).setFontAngle(90);

// Add a vertical mark at x = 17 using a semi-transparent purple (809933ff) color and Arial Bold
// font. Attached the mark (and therefore its label) to the top x axis.
Mark mark = c.xAxis2().addMark(17, 0x809933ff, "Merge with Star Tech", "Arial Bold");

// Set the mark line width to 2 pixels
mark.setLineWidth(2);

// Set the mark label font color to purple (0x9933ff)
mark.setFontColor(0x9933ff);

// Add a copyright message at (575, 295) (bottom right of plot area) using Arial Bold font
ChartDirector.TextBox copyRight = c.addText(575, 295, "(c) Copyright Space Travel Ltd", "Arial Bold"
    );
copyRight.setAlignment(Chart.BottomRight);

// Add a line layer to the chart
LineLayer layer = c.addLineLayer();

// Set the default line width to 3 pixels
layer.setLineWidth(3);

// Add the data sets to the line layer
layer.addDataSet(data0, -1, "Enterprise");
layer.addDataSet(data1, -1, "Consumer");

// Create the image
String chart1URL = c.makeSession(request, "chart1");

// Create an image map for the chart
String chartImageMap = c.getHTMLImageMap("xystub.jsp", "",
    "title='{dataSetName} @ {xLabel} = USD {value|0} millions'");

// Create an image map for the legend box
String legendImageMap = legendBox.getHTMLImageMap(
    "javascript:popMsg('the legend key [{dataSetName}]');", " ",
    "title='This legend key is clickable!'");

// Obtain the image map coordinates for the title, mark, and copyright message. These will be used
// to define the image map inline. (See HTML code below.)
String titleCoor = title.getImageCoor();
String markCoor = mark.getImageCoor();
String copyRightCoor = copyRight.getImageCoor();
%>
<!DOCTYPE html>
<html>
<head>
    <title>Custom Clickable Objects</title>
</head>
<body style="margin:5px 0px 0px 5px">
<script type="text/javascript">
function popMsg(msg) {
    alert("You have clicked on " + msg + ".");
}
</script>
<div style="font:bold 18pt verdana;">
    Custom Clickable Objects
</div>
<hr style="border:solid 1px #000080" />
<div style="font:10pt verdana; margin-bottom:20px">
    <a href='viewsource.jsp?file=<%=request.getServletPath()%>'>View Source Code</a>
</div>
<div style="font:10pt verdana; width:600px; margin-bottom:20px">
    In the following chart, the lines, legend keys, title, copyright, and the "Merge
    with Star Tech" text are all clickable!
</div>
<img src="<%=response.encodeURL("getchart.jsp?"+chart1URL)%>" border="0" usemap="#map1">
<map name="map1">
<%=chartImageMap%>
<%=legendImageMap%>
<area <%=titleCoor%>  href='javascript:popMsg("the chart title");'
    title='The title is clickable!' />
<area <%=markCoor%> href='javascript:popMsg("the Merge with Star Tech mark");'
    title='The "Merge with Star Tech" text is clickable!' />
<area <%=copyRightCoor%> href='javascript:popMsg("the copyright message");'
    title='The copyright text is clickable!' />
</map>
</body>
</html>

The above code is quite similar to most of the sample codes in this documentation, so it will not be discussed in detail. The main difference is the code for creating the image map.

The image map in this example consists of multiple parts. The part for the line chart is produced using BaseChart.getHTMLImageMap with "xystub.jsp" as the handler:

String chartImageMap = c.getHTMLImageMap("xystub.jsp", "",
    "title='{dataSetName} @ {xLabel} = USD {value|0} millions'");

For demo purpose, the handler simple displays information on what is clicked. It's code is as follows.

[JSP Version] jspdemo/xystub.jsp
<!DOCTYPE html>
<html>
<head>
    <title>Simple Clickable XY Chart Handler</title>
</head>
<body style="margin:5px 0px 0px 5px">
<div style="font:bold 18pt verdana;">
    Simple Clickable XY Chart Handler
</div>
<hr style="border:solid 1px #000080" />
<div style="font-size:10pt verdana; margin-bottom:20px">
    <a href="viewsource.jsp?file=<%=request.getServletPath()%>">View Source Code</a>
</div>
<div style="font:10pt verdana;">
<b>You have clicked on the following chart element :</b><br />
<ul>
    <li>Data Set : <%=request.getParameter("dataSetName")%></li>
    <li>X Position : <%=request.getParameter("x")%></li>
    <li>X Label : <%=request.getParameter("xLabel")%></li>
    <li>Data Value : <%=request.getParameter("value")%></li>
</ul>
</div>
</body>
</html>

The image map for the legend keys is produced using LegendBox.getHTMLImageMap. In this example, client side Javascript will be executed when the user clicks on the legend key.

String legendImageMap = legendBox.getHTMLImageMap(
    "javascript:popMsg('the legend key [{dataSetName}]');", " ",
    "title='This legend key is clickable!'");

As shown above, the "javascript:popMsg(...);" as used in the url parameter of "getHTMLImageMap". The browser will interpret it as a client side Javascript statement to be executed when the <AREA> tag is clicked.

Note that the second argument to LegendBox.getHTMLImageMap is set to a space character. This argument specifies the HTTP query parameters to be appended to the url. In this example, as the url is actually client side Javascript, no query parameter is necessary. So a space character is used. (We cannot use an empty string, as it means default query parameters, not no query parameter.)

The client side Javascript executed in this example just pops up a message.

<script type="text/javascript">
function popMsg(msg) {
    alert("You have clicked on " + msg + ".");
}
</script>

Most text messages in ChartDirector are represented as TextBox objects. Their image map coordinates can be retrieved using Box.getImageCoor. This allows <AREA> tags for TextBox objects be constructed easily. This example illustrates how to use this method to create image maps for the chart title, mark label, and the copyright message.

String titleCoor = title.getImageCoor();
String markCoor = mark.getImageCoor();
String copyRightCoor = copyRight.getImageCoor();

The image map coordinates are then used to make <AREA> tags as follows:

<area <%=titleCoor%> href='javascript:popMsg("the chart title");'
    title='The title is clickable!'>
<area <%=markCoor%> href='javascript:popMsg("the Merge with Star Tech mark");'
    title='The "Merge with Star Tech" text is clickable!'>
<area <%=copyRightCoor%> href='javascript:popMsg("the copyright message");'
    title='The copyright text is clickable!'>