ChartDirector 6.1 (Java Edition)

Track Line with Axis Labels (Windows)




NOTE: This section describes Track Line with Axis Labels for Windows applications only. For web applications, please refer to Track Line with Axis Labels (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 trackLineAxis method is the routine that draws the track cursor. Its key elements are:

Source Code Listing

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

public class trackaxis implements DemoModule
{
    //
    // The main method to allow this demo to run as a standalone program.
    //
    public static void main(String args[]) 
    {
        trackaxis demo = new trackaxis();
        demo.display();
        System.exit(0);
    }

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

        // Add a movedMovedPlotArea event listener to draw the track cursor
        viewer.addTrackCursorListener(new TrackCursorAdapter() {
            public void mouseMovedPlotArea(MouseEvent e) {
                chartViewer1_MouseMovedPlotArea(e);
            }
        });
        
        // Draw the chart
        drawChart(viewer);

        // Layout and display the JDialog
        d.pack();
        d.setVisible(true);
    }
  
    //
    // Main code for creating charts
    //
    public void drawChart(ChartViewer viewer)
    {
        // Data for the chart as 2 random data series
        RanSeries r = new RanSeries(127);
        double[] data0 = r.getSeries(180, 10, -1.5, 1.5);
        double[] data1 = r.getSeries(180, 150, -15, 15);
        Date[] timeStamps = r.getDateSeries(180, new GregorianCalendar(2011, 0, 1).getTime(), 86400);

        // Create a XYChart object of size 670 x 400 pixels
        XYChart c = new XYChart(670, 400);

        // Add a title to the chart using 18pt Times New Roman Bold Italic font
        c.addTitle("Plasma Stabilizer Energy Usage", "Times New Roman Bold Italic", 18);

        // Set the plotarea at (50, 55) with width 100 pixels less than chart width, and height 90 pixels less
        // than chart height. Use a vertical gradient from light blue (f0f6ff) to sky blue (a0c0ff) as
        // background. Set border to transparent and grid lines to white (ffffff).
        c.setPlotArea(50, 55, c.getWidth() - 100, c.getHeight() - 90, c.linearGradientColor(0, 55, 0,
            c.getHeight() - 35, 0xf0f6ff, 0xa0c0ff), -1, Chart.Transparent, 0xffffff, 0xffffff);

        // Add a legend box at (50, 25) using horizontal layout. Use 10pt Arial Bold as font. Set the
        // background and border color to Transparent.
        c.addLegend(50, 25, false, "Arial Bold", 10).setBackground(Chart.Transparent);

        // Set axis label style to 8pt Arial Bold
        c.xAxis().setLabelStyle("Arial Bold", 8);
        c.yAxis().setLabelStyle("Arial Bold", 8);
        c.yAxis2().setLabelStyle("Arial Bold", 8);

        // Set the axis stem to transparent
        c.xAxis().setColors(Chart.Transparent);
        c.yAxis().setColors(Chart.Transparent);
        c.yAxis2().setColors(Chart.Transparent);

        // Configure x-axis label format
        c.xAxis().setMultiFormat(Chart.StartOfYearFilter(), "{value|mm/yyyy} ", Chart.StartOfMonthFilter(),
            "{value|mm}");

        // Add axis title using 10pt Arial Bold Italic font
        c.yAxis().setTitle("Power Usage (Watt)", "Arial Bold Italic", 10);
        c.yAxis2().setTitle("Effective Load (kg)", "Arial Bold Italic", 10);

        // Add a line layer to the chart using a line width of 2 pixels.
        LineLayer layer = c.addLineLayer2();
        layer.setLineWidth(2);

        // Add 2 data series to the line layer
        layer.setXData(timeStamps);
        layer.addDataSet(data0, 0xcc0000, "Power Usage");
        layer.addDataSet(data1, 0x008800, "Effective Load").setUseYAxis2();

        // Assign the chart to the ChartViewer
        viewer.setChart(c);
    }

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

        // Hide the track cursor when the mouse leaves the plot area
        viewer.removeDynamicLayer("MouseExitedPlotArea");
    }

    //
    // Draw track line with axis labels
    //
    private void trackLineAxis(XYChart c, int mouseX)
    {
        // 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, and find its pixel coordinate.
        double xValue = c.getNearestXValue(mouseX);
        int xCoor = c.getXCoor(xValue);

        // The vertical track line is drawn up to the highest data point (the point with smallest
        // y-coordinate). We need to iterate all datasets in all layers to determine where it is.
        int minY = plotArea.getBottomY();

        // Iterate through all layers to find the highest data point
        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);

                double dataPoint = dataSet.getPosition(xIndex);
                if ((dataPoint != Chart.NoValue) && (dataSet.getDataColor() != Chart.Transparent)) {
                    minY = Math.min(minY, c.getYCoor(dataPoint, dataSet.getUseYAxis()));
                }
            }
        }

        // Draw a vertical track line at the x-position up to the highest data point.
        d.vline(Math.max(minY, plotArea.getTopY()), plotArea.getBottomY() + 6, xCoor, d.dashLineColor(
            0x000000, 0x0101));

        // Draw a label on the x-axis to show the track line position
        d.text("<*font,bgColor=000000*> " + c.xAxis().getFormattedLabel(xValue, "mmm dd, yyyy") +
            " <*/font*>", "Arial Bold", 8).draw(xCoor, plotArea.getBottomY() + 6, 0xffffff, Chart.Top);

        // 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);

                // The positional value, axis binding, pixel coordinate and color of the data point.
                double dataPoint = dataSet.getPosition(xIndex);
                Axis yAxis = dataSet.getUseYAxis();
                int yCoor = c.getYCoor(dataPoint, yAxis);
                int color = dataSet.getDataColor();

                // Draw the axis label only for visible data points of named data sets
                if ((dataPoint != Chart.NoValue) && (color != Chart.Transparent) && (yCoor >=
                    plotArea.getTopY()) && (yCoor <= plotArea.getBottomY())) {
                    // The axis label consists of 3 parts - a track dot for the data point, an axis label, and
                    // a line joining the track dot to the axis label.

                    // Draw the line first. The end point of the line at the axis label side depends on
                    // whether the label is at the left or right side of the axis (that is, on whether the
                    // axis is on the left or right side of the plot area).
                    int xPos = yAxis.getX() + ((yAxis.getAlignment() == Chart.Left) ? -4 : 4);
                    d.hline(xCoor, xPos, yCoor, d.dashLineColor(color, 0x0101));

                    // Draw the track dot
                    d.circle(xCoor, yCoor, 4, 4, color, color);

                    // Draw the axis label. If the axis is on the left side of the plot area, the labels
                    // should right aligned to the axis, and vice versa.
                    d.text("<*font,bgColor=" + Integer.toHexString(color) + "*> " + c.formatValue(dataPoint,
                        "{value|P4}") + " <*/font*>", "Arial Bold", 8).draw(xPos, yCoor, 0xffffff, ((
                        yAxis.getAlignment() == Chart.Left) ? Chart.Right : Chart.Left));
                }
            }
        }
    }
    
    //
    // Implementation of the DemoModule interface to allow this demo to run inside the 
    // ChartDirectorDemo browser
    //
    
    // Name of demo program
    public String toString() 
    { 
        return "Track Line with Axis Labels"; 
    }

    // 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.
        display();
        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
    }
}