ChartDirector 6.1 (Java Edition)

Track Box with Floating Legend (Windows)

NOTE: This section describes Track Box with Floating Legend for Windows applications only. For web applications, please refer to Track Box with Floating Legend (Web).

This sample program demonstrates a track cursor programmed with the following features:

The code first draws the chart. Then in the TrackCursorListener.mouseMovedPlotArea event handler, the track cursor is drawn to reflect the mouse position. The track cursor is configured to automatically hide itself when the mouse leaves the plot area.

The trackBoxLegend method is the routine that draws the track cursor. Its key elements are:

Source Code Listing

[Java Version] javademo/
import ChartDirector.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;

public class trackbox implements DemoModule
    // The main method to allow this demo to run as a standalone program.
    public static void main(String args[]) 
        trackbox demo = new trackbox();

    // Display the window
    private void display() 
        // Use a JDialog as the window
           JDialog d = new JDialog((java.awt.Frame)null, toString(), true);
        // Create the ChartViewer and add it to the JDialog
        ChartViewer viewer = new ChartViewer();

        // Add a movedMovedPlotArea event listener to draw the track cursor
        viewer.addTrackCursorListener(new TrackCursorAdapter() {
            public void mouseMovedPlotArea(MouseEvent e) {
        // Draw the chart

        // Layout and display the JDialog
    // Main code for creating charts
    public void drawChart(ChartViewer viewer)
        // The data for the bar chart
        double[] data0 = {100, 125, 245, 147, 67};
        double[] data1 = {85, 156, 179, 211, 123};
        double[] data2 = {97, 87, 56, 267, 157};
        String[] labels = {"Mon", "Tue", "Wed", "Thur", "Fri"};

        // Create a XYChart object of size 540 x 375 pixels
        XYChart c = new XYChart(540, 375);

        // Add a title to the chart using 18pt Times Bold Italic font
        c.addTitle("Average Weekly Network Load", "Times New Roman Bold Italic", 18);

        // Set the plotarea at (50, 55) and of 440 x 280 pixels in size. Use a vertical gradient color from
        // light blue (f9f9ff) to blue (6666ff) as background. Set border and grid lines to white (ffffff).
        c.setPlotArea(50, 55, 440, 280, c.linearGradientColor(0, 55, 0, 335, 0xf9f9ff, 0x6666ff), -1,
            0xffffff, 0xffffff);

        // Add a legend box at (50, 28) using horizontal layout. Use 10pt Arial Bold as font, with transparent
        // background.
        c.addLegend(50, 28, false, "Arial Bold", 10).setBackground(Chart.Transparent);

        // Set the x axis labels

        // Draw the ticks between label positions (instead of at label positions)

        // Set axis label style to 8pt Arial Bold
        c.xAxis().setLabelStyle("Arial Bold", 8);
        c.yAxis().setLabelStyle("Arial Bold", 8);

        // Set axis line width to 2 pixels

        // Add axis title
        c.yAxis().setTitle("Throughput (MBytes Per Hour)");

        // Add a multi-bar layer with 3 data sets
        BarLayer layer = c.addBarLayer2(Chart.Side);
        layer.addDataSet(data0, 0xff0000, "Server #1");
        layer.addDataSet(data1, 0x00ff00, "Server #2");
        layer.addDataSet(data2, 0xff8800, "Server #3");

        // Set bar border to transparent. Use glass lighting effect with light direction from left.
        layer.setBorderColor(Chart.Transparent, Chart.glassEffect(Chart.NormalGlare, Chart.Left));

        // Configure the bars within a group to touch each others (no gap)
        layer.setBarGap(0.2, Chart.TouchBar);

        // Assign the chart to the ChartViewer

    // Draw track cursor when mouse is moving over plotarea
    private void chartViewer1_MouseMovedPlotArea(MouseEvent e)
        ChartViewer viewer = (ChartViewer)e.getSource();
        trackBoxLegend((XYChart)viewer.getChart(), viewer.getPlotAreaMouseX(), viewer.getPlotAreaMouseY());

        // Hide the track cursor when the mouse leaves the plot area

    // Draw the track box with legend
    private void trackBoxLegend(XYChart c, int mouseX, int mouseY)
        // Clear the current dynamic layer and get the DrawArea object to draw on it.
        DrawArea d = c.initDynamicLayer();

        // The plot area object
        PlotArea plotArea = c.getPlotArea();

        // Get the data x-value that is nearest to the mouse
        double xValue = c.getNearestXValue(mouseX);

        // Compute the position of the box. This example assumes a label based x-axis, in which the labeling
        // spacing is one x-axis unit. So the left and right sides of the box is 0.5 unit from the central
        // x-value.
        int boxLeft = c.getXCoor(xValue - 0.5);
        int boxRight = c.getXCoor(xValue + 0.5);
        int boxTop = plotArea.getTopY();
        int boxBottom = plotArea.getBottomY();

        // Draw the track box
        d.rect(boxLeft, boxTop, boxRight, boxBottom, 0x000000, Chart.Transparent);

        // Container to hold the legend entries
        ArrayList legendEntries = new ArrayList();

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

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

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

                // Build the legend entry, consist of the legend icon, the name and the data value.
                double dataValue = dataSet.getValue(xIndex);
                if ((dataValue != Chart.NoValue) && (dataSet.getDataColor() != Chart.Transparent)) {
                    legendEntries.add(dataSet.getLegendIcon() + " " + dataSet.getDataName() + ": " +
                        c.formatValue(dataValue, "{value|P4}"));

        // Create the legend by joining the legend entries
        if (legendEntries.size() > 0) {
            String legend = "<*block,bgColor=FFFFCC,edgeColor=000000,margin=5*><*font,underline=1*>" +
                c.xAxis().getFormattedLabel(xValue) + "<*/font*><*br*>" + Chart.stringJoin(legendEntries,
                "<*br*>") + "<*/*>";

            // Display the legend at the bottom-right side of the mouse cursor, and make sure the legend will
            // not go outside the chart image.
            TTFText t = d.text(legend, "Arial Bold", 8);
            t.draw(Math.min(mouseX + 12, c.getWidth() - t.getWidth()), Math.min(mouseY + 18, c.getHeight() -
                t.getHeight()), 0x000000, Chart.TopLeft);
    // Implementation of the DemoModule interface to allow this demo to run inside the 
    // ChartDirectorDemo browser
    // Name of demo program
    public String toString() 
        return "Track Box with Floating Legend"; 

    // Number of charts produced in this demo
    public int getNoOfCharts() 
        // This demo open its own dialog instead of using the right pane of the ChartDirectorDemo 
        // for display. We just display the dialog, then return 0.
        return 0; 

    // Main code for creating charts
    public void createChart(ChartViewer viewer, int chartIndex)
        // do nothing, as the ChartDirectorDemo browser right pane is not used