Real-Time Chart with Track Line

[JSP Version] jspdemo/realtimetrack.jsp
<%@page import="ChartDirector.*, java.util.*" %>
<%!
//
// Draw the chart
//
private void drawChart(WebChartViewer viewer)
{
    //
    // Data to draw the chart. In this demo, the data buffer will be filled by a random data
    // generator. In real life, the data is probably stored in a buffer (eg. a database table, a
    // text file, or some global memory) and updated by other means.
    //

    // We use a data buffer to emulate the last 240 samples.
    int sampleSize = 240;
    double[] dataSeries1 = new double[sampleSize];
    double[] dataSeries2 = new double[sampleSize];
    double[] dataSeries3 = new double[sampleSize];
    Date[] timeStamps = new Date[sampleSize];

    // Our pseudo random number generator
    double firstDate = new Date().getTime() / 1000 - timeStamps.length;
    for(int i = 0; i < timeStamps.length; ++i) {
        double p = firstDate + i;
        timeStamps[i] = new Date((long)p * 1000);
        dataSeries1[i] = Math.cos(p * 2.1) * 10 + 1 / (Math.cos(p) * Math.cos(p) + 0.01) + 20;
        dataSeries2[i] = 100 * Math.sin(p / 27.7) * Math.sin(p / 10.1) + 150;
        dataSeries3[i] = 100 * Math.cos(p / 6.7) * Math.cos(p / 11.9) + 150;
    }

    // Create an XYChart object 600 x 270 pixels in size, with light grey (f4f4f4) background, black
    // (000000) border, 1 pixel raised effect, and with a rounded frame.
    XYChart c = new XYChart(600, 270, 0xf4f4f4, 0x000000, 0);
    c.setRoundedFrame();

    // Set the plotarea at (55, 57) and of size 520 x 185 pixels. Use white (ffffff) background.
    // Enable both horizontal and vertical grids by setting their colors to grey (cccccc). Set
    // clipping mode to clip the data lines to the plot area.
    c.setPlotArea(55, 57, 520, 185, 0xffffff, -1, -1, 0xcccccc, 0xcccccc);
    c.setClipping();

    // Add a title to the chart using 15pt Times New Roman Bold Italic font, with a light grey
    // (dddddd) background, black (000000) border, and a glass like raised effect.
    c.addTitle("Field Intensity at Observation Satellite", "Times New Roman Bold Italic", 15
        ).setBackground(0xdddddd, 0x000000, Chart.glassEffect());

    // Configure the y-axis with a 10pt Arial Bold axis title
    c.yAxis().setTitle("Intensity (V/m)", "Arial Bold", 10);

    // Configure the x-axis to auto-scale with at least 75 pixels between major tick and 15 pixels
    // between minor ticks. This shows more minor grid lines on the chart.
    c.xAxis().setTickDensity(75, 15);

    // Set the axes width to 2 pixels
    c.xAxis().setWidth(2);
    c.yAxis().setWidth(2);

    // Set the x-axis label format
    c.xAxis().setLabelFormat("{value|hh:nn:ss}");

    // Create a line layer to plot the lines
    LineLayer layer = c.addLineLayer2();

    // The x-coordinates are the timeStamps.
    layer.setXData(timeStamps);

    // The 3 data series are used to draw 3 lines. Here we put the latest data values as part of the
    // data set name, so you can see them updated in the legend box.
    layer.addDataSet(dataSeries1, 0xff0000, "Alpha");
    layer.addDataSet(dataSeries2, 0x00cc00, "Beta");
    layer.addDataSet(dataSeries3, 0x0000ff, "Gamma");

    // Output the chart
    viewer.setChart(c, Chart.SVG);

    // Output Javascript chart model to the browser to support tracking cursor
    viewer.setChartModel(c.getJsChartModel());
}
%>
<%

//
// This script handles both the full page request, as well as the subsequent partial updates (AJAX
// chart updates). We need to determine the type of request first before we processing it.
//

// Create the WebChartViewer object
WebChartViewer viewer = new WebChartViewer(request, "chart1");

if (viewer.isPartialUpdateRequest()) {
    // Is a partial update request. Draw the chart and perform a partial response.
    drawChart(viewer);
    out.clear();
    viewer.partialUpdateChart(response);
    return;
}

//
// If the code reaches here, it is a full page request.
//

drawChart(viewer);
%>
<!DOCTYPE html>
<html>
<head>
    <title>Real-Time Chart with Track Line</title>
    <script type="text/javascript" src="cdjcv.js"></script>
</head>
<body style="margin:0px">
<script type="text/javascript">

//
// Execute the following initialization code after the web page is loaded
//
JsChartViewer.addEventListener(window, 'load', function() {
    var viewer = JsChartViewer.get('<%=viewer.getId()%>');

    // Draw track cursor when mouse is moving over plotarea or if the chart is updated. In the latter case,
    // if the mouse is not on the plot area, we will update the legend to show the latest data values.
    viewer.attachHandler(["MouseMovePlotArea", "TouchStartPlotArea", "TouchMovePlotArea", "ChartMove",
        "PostUpdate", "Now"], function(e) {
        this.preventDefault(e);   // Prevent the browser from using touch events for other actions
        trackLineLegend(viewer, viewer.getPlotAreaMouseX());
    });

    // When the chart is being updated, by default, an "Updating" box will pop up. In this example, we
    // will disable this box.
    viewer.updatingMsg = "";
});

//
// Draw track line with legend
//
function trackLineLegend(viewer, mouseX)
{
    // Remove all previously drawn tracking object
    viewer.hideObj("all");

    // The chart and its plot area
    var c = viewer.getChart();
    var plotArea = c.getPlotArea();

    // Get the data x-value that is nearest to the mouse, and find its pixel coordinate.
    var xValue = c.getNearestXValue(mouseX);
    var xCoor = c.getXCoor(xValue);
    if (xCoor == null)
        return;

    // Draw a vertical track line at the x-position
    viewer.drawVLine("trackLine", xCoor, plotArea.getTopY(), plotArea.getBottomY(), "black 1px dotted");

    // Array to hold the legend entries
    var legendEntries = [];

    // Iterate through all layers to build the legend array
    for (var i = 0; i < c.getLayerCount(); ++i)
    {
        var layer = c.getLayerByZ(i);

        // The data array index of the x-value
        var xIndex = layer.getXIndexOf(xValue);

        // Iterate through all the data sets in the layer
        for (var j = 0; j < layer.getDataSetCount(); ++j)
        {
            var dataSet = layer.getDataSetByZ(j);

            // We are only interested in visible data sets with names, as they are required for legend entries.
            var dataName = dataSet.getDataName();
            var color = dataSet.getDataColor();
            if ((!dataName) || (color == null))
                continue;

            // Build the legend entry, consist of a colored square box, the name and the data value.
            var dataValue = dataSet.getValue(xIndex);
            legendEntries.push("<nobr>" + viewer.htmlRect(7, 7, color) + " " + dataName + ": " +
                ((dataValue == null) ? "N/A" : dataValue.toPrecision(4)) + viewer.htmlRect(20, 0) + "</nobr> ");

            // Draw a track dot for data points within the plot area
            var yCoor = c.getYCoor(dataSet.getPosition(xIndex), dataSet.getUseYAxis());
            if ((yCoor != null) && (yCoor >= plotArea.getTopY()) && (yCoor <= plotArea.getBottomY()))
            {
                viewer.showTextBox("dataPoint" + i + "_" + j, xCoor, yCoor, JsChartViewer.Center,
                    viewer.htmlRect(7, 7, color));
            }
        }
    }

    // Create the legend by joining the legend entries.
    var legend = "<nobr>[" + c.xAxis().getFormattedLabel(xValue, "hh:nn:ss") + "]" + viewer.htmlRect(20, 0) +
        "</nobr> " + legendEntries.reverse().join("");

    // Display the legend on the top of the plot area
    viewer.showTextBox("legend", plotArea.getLeftX(), plotArea.getTopY(), JsChartViewer.BottomLeft, legend,
        "width:" + plotArea.getWidth() + "px;font:bold 11px Arial;padding:3px;-webkit-text-size-adjust:100%;");
}

//
// Executes once every second to update the countdown display. Updates the chart when the countdown reaches 0.
//
function timerTick()
{
    // Get the update period and the time left
    var updatePeriod = parseInt(document.getElementById("UpdatePeriod").value);
    var timeLeft = Math.min(parseInt(document.getElementById("TimeRemaining").innerHTML), updatePeriod) - 1;

    if (timeLeft == 0)
        // Can update the chart now
        JsChartViewer.get('<%=viewer.getId()%>').partialUpdate();
    else if (timeLeft < 0)
        // Reset the update period
        timeLeft += updatePeriod;

    // Update the countdown display
    document.getElementById("TimeRemaining").innerHTML = timeLeft;
}
window.setInterval("timerTick()", 1000);

</script>
<table cellspacing="0" cellpadding="0" border="0">
    <tr>
        <td align="right" colspan="2" style="background:#000088; color:#ffff00; padding:0px 4px 2px 0px;">
            <a style="color:#FFFF00; font:italic bold 10pt Arial; text-decoration:none" href="http://www.advsofteng.com/">
                Advanced Software Engineering
            </a>
        </td>
    </tr>
    <tr valign="top">
        <td style="width:150px; background:#c0c0ff; border-right:black 1px solid; border-bottom:black 1px solid;">
            <br />
            <br />
            <div style="font: 9pt Verdana; padding:10px;">
                <b>Update Period</b><br />
                <select id="UpdatePeriod" style="width:130px">
                    <option value="5">5</option>
                    <option value="10" selected="selected">10</option>
                    <option value="20">20</option>
                    <option value="30">30</option>
                    <option value="60">60</option>
                </select>
            </div>
            <div style="font:9pt Verdana; padding:10px;">
                <b>Time Remaining</b><br />
                <div style="width:128px; border:#888888 1px inset;">
                    <div style="margin:3px" id="TimeRemaining">0</div>
                </div>
            </div>
        </td>
        <td>
            <div style="font: bold 20pt Arial; margin:5px 0px 0px 5px;">
                Real-Time Chart with Track Line
            </div>
            <hr style="border:solid 1px #000080" />
            <div style="padding:0px 5px 5px 10px">
                <!-- ****** Here is the chart image ****** -->
                <%=viewer.renderHTML(response)%>
            </div>
        </td>
    </tr>
</table>
</body>
</html>