ChartDirector 7.0 (Java Edition)

Track Line with Axis Labels




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

On the server side, the code draws the chart as usual, and outputs both the image and the Javascript Chart Model of the chart.

The trackLineAxis Javascript function is the routine that draws the track cursor. Its key elements are:

Source Code Listing

[JSP Version] jspdemo/trackaxis.jsp
<%@page import="ChartDirector.*, java.util.*" %> <% // 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(); // Create the WebChartViewer object WebChartViewer viewer = new WebChartViewer(request, "chart1"); // Output the chart viewer.setChart(c, Chart.SVG); // Output Javascript chart model to the browser to support tracking cursor viewer.setChartModel(c.getJsChartModel()); %> <!DOCTYPE html> <html> <head> <title>Track Line with Axis Labels</title> <script type="text/javascript" src="cdjcv.js"></script> </head> <body style="margin:5px 0px 0px 5px"> <script type="text/javascript"> // // Use the window load event to set up the MouseMovePlotArea event handler // JsChartViewer.addEventListener(window, 'load', function() { var viewer = JsChartViewer.get('<%=viewer.getId()%>'); // Draw track cursor when mouse is moving over plotarea. Hide it when mouse leaves plot area. viewer.attachHandler(["MouseMovePlotArea", "TouchStartPlotArea", "TouchMovePlotArea", "ChartMove"], function(e) { this.preventDefault(e); // Prevent the browser from using touch events for other actions trackLineAxis(viewer, viewer.getPlotAreaMouseX()); viewer.setAutoHide("all", ["MouseOutPlotArea", "TouchEndPlotArea"]); }); }); // // Draw track line with axis labels // function trackLineAxis(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); // 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. var minY = plotArea.getBottomY(); // Iterate through all layers to find the highest data point 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); var yCoor = c.getYCoor(dataSet.getPosition(xIndex), dataSet.getUseYAxis()); if ((yCoor != null) && (dataSet.getDataColor() != null)) minY = Math.min(minY, yCoor); } } // Draw a vertical track line at the x-position up to the highest data point. viewer.drawVLine("trackLine", xCoor, Math.max(minY, plotArea.getTopY()), plotArea.getBottomY() + 3, "black 1px dotted"); // Draw a label on the x-axis to show the track line position viewer.showTextBox("xAxisLabel", xCoor, plotArea.getBottomY() + 3, JsChartViewer.Top, c.xAxis().getFormattedLabel(xValue, "mmm dd, yyyy"), "font:bold 11px Arial;color:#FFFFFF;background-color:#000000;padding:2px 3px"); // Iterate through all layers to draw the axis labels for the data points 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); // The positional value, axis binding, pixel coordinate and color of the data point. var dataPoint = dataSet.getPosition(xIndex); var yAxis = dataSet.getUseYAxis(); var yCoor = c.getYCoor(dataPoint, yAxis); var color = dataSet.getDataColor(); // Draw the axis label only for visible data points of named data sets if ((yCoor != null) && (yCoor >= plotArea.getTopY()) && (yCoor <= plotArea.getBottomY()) && (color != null)) { // 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). var xPos = yAxis.getX() + ((yAxis.getAlignment() == JsChartViewer.Left) ? -4 : 4); viewer.drawHLine("joinLine" + i + "_" + j, yCoor, xPos, xCoor, color + " 1px dotted"); // 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. viewer.showTextBox("yAxisLabel" + i + "_" + j, xPos, yCoor, (yAxis.getAlignment() == JsChartViewer.Left) ? JsChartViewer.Right : JsChartViewer.Left, dataPoint.toPrecision(4), "padding:2px 3px;font:bold 11px Arial;background-color:" + color + ";color:#FFFFFF;-webkit-text-size-adjust:100%;"); // Draw the track dot viewer.showTextBox("dataPoint" + i + "_" + j, xCoor, yCoor, JsChartViewer.Center, viewer.htmlRect(7, 7, color)); } } } } </script> <div style="font-size:18pt; font-family:verdana; font-weight:bold"> Track Line with Axis Labels </div> <hr style="border:solid 1px #000080" /> <div style="font-size:10pt; font-family:verdana; margin-bottom:1.5em"> <a href="viewsource.jsp?file=<%=request.getServletPath()%>">View Source Code</a> </div> <!-- ****** Here is the chart image ****** --> <%=viewer.renderHTML(response)%> </body> </html>