ChartDirector 6.2 (.NET Edition)

Track Line with Data Labels (Windows)




NOTE: This section describes Track Line with Data Labels for Windows applications only. For web applications, please refer to Track Line with Data Labels (Web).

NOTE: For conciseness, some of the following descriptions only mention WinChartViewer. Those descriptions apply to WPFChartViewer as well.

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

The code first draws the chart. Then in the WinChartViewer.MouseMovePlotArea 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 trackLineLabel method is the routine that draws the track cursor. Its key elements are:

Source Code Listing

[Windows Forms - C# version] NetWinCharts\CSharpWinCharts\frmtracklabel.cs
using System;
using System.Collections;
using System.Windows.Forms;
using ChartDirector;

namespace CSharpChartExplorer
{
    public partial class FrmTrackLabel : Form
    {
        public FrmTrackLabel()
        {
            InitializeComponent();
        }

        private void FrmTrackLabel_Load(object sender, EventArgs e)
        {
            // Data for the chart as 3 random data series
            RanSeries r = new RanSeries(127);
            double[] data0 = r.getSeries(100, 100, -15, 15);
            double[] data1 = r.getSeries(100, 150, -15, 15);
            double[] data2 = r.getSeries(100, 200, -15, 15);
            DateTime[] timeStamps = r.getDateSeries(100, new DateTime(2011, 1, 1), 86400);

            // Create a XYChart object of size 640 x 400 pixels
            XYChart c = new XYChart(640, 400);

            // Add a title to the chart using 18pt Times New Roman Bold Italic font
            c.addTitle("    Product Line Global Revenue", "Times New Roman Bold Italic", 18);

            // Set the plotarea at (50, 55) with width 70 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() - 70, 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);

            // Set the axis stem to transparent
            c.xAxis().setColors(Chart.Transparent);
            c.yAxis().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("USD millions", "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 3 data series to the line layer
            layer.setXData(timeStamps);
            layer.addDataSet(data0, 0xff3333, "Alpha");
            layer.addDataSet(data1, 0x008800, "Beta");
            layer.addDataSet(data2, 0x3333cc, "Gamma");

            // Assign the chart to the WinChartViewer
            winChartViewer1.Chart = c;
        }

        //
        // Draw track cursor when mouse is moving over plotarea
        //
        private void winChartViewer1_MouseMovePlotArea(object sender, MouseEventArgs e)
        {
            WinChartViewer viewer = (WinChartViewer)sender;
            trackLineLabel((XYChart)viewer.Chart, viewer.PlotAreaMouseX);
            viewer.updateDisplay();

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

        //
        // Draw track line with data labels
        //
        private void trackLineLabel(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);

            // Draw a vertical track line at the x-position
            d.vline(plotArea.getTopY(), plotArea.getBottomY(), xCoor, d.dashLineColor(0x000000, 0x0101));

            // Draw a label on the x-axis to show the track line position.
            string xlabel = "<*font,bgColor=000000*> " + c.xAxis().getFormattedLabel(xValue, "mmm dd, yyyy") +
                " <*/font*>";
            TTFText t = d.text(xlabel, "Arial Bold", 8);

            // Restrict the x-pixel position of the label to make sure it stays inside the chart image.
            int xLabelPos = Math.Max(0, Math.Min(xCoor - t.getWidth() / 2, c.getWidth() - t.getWidth()));
            t.draw(xLabelPos, plotArea.getBottomY() + 6, 0xffffff);

            // Iterate through all layers to draw the data labels
            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);

                    // Get the color and position of the data label
                    int color = dataSet.getDataColor();
                    int yCoor = c.getYCoor(dataSet.getPosition(xIndex), dataSet.getUseYAxis());

                    // Draw a track dot with a label next to it for visible data points in the plot area
                    if ((yCoor >= plotArea.getTopY()) && (yCoor <= plotArea.getBottomY()) && (color !=
                        Chart.Transparent)) {

                        d.circle(xCoor, yCoor, 4, 4, color, color);

                        string label = "<*font,bgColor=" + color.ToString("x") + "*> " + c.formatValue(
                            dataSet.getValue(xIndex), "{value|P4}") + " <*/font*>";
                        t = d.text(label, "Arial Bold", 8);

                        // Draw the label on the right side of the dot if the mouse is on the left side the
                        // chart, and vice versa. This ensures the label will not go outside the chart image.
                        if (xCoor <= (plotArea.getLeftX() + plotArea.getRightX()) / 2) {
                            t.draw(xCoor + 5, yCoor, 0xffffff, Chart.Left);
                        } else {
                            t.draw(xCoor - 5, yCoor, 0xffffff, Chart.Right);
                        }
                    }
                }
            }
        }
    }
}

[Windows Forms - VB Version] NetWinCharts\VBNetWinCharts\frmtracklabel.vb
Imports ChartDirector
Imports System.Collections

Public Class FrmTrackLabel

    Private Sub FrmTrackLabel_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load

        ' Data for the chart as 3 random data series
        Dim r As RanSeries = New RanSeries(127)
        Dim data0() As Double = r.getSeries(100, 100, -15, 15)
        Dim data1() As Double = r.getSeries(100, 150, -15, 15)
        Dim data2() As Double = r.getSeries(100, 200, -15, 15)
        Dim timeStamps() As Date = r.getDateSeries(100, DateSerial(2011, 1, 1), 86400)

        ' Create a XYChart object of size 640 x 400 pixels
        Dim c As XYChart = New XYChart(640, 400)

        ' Add a title to the chart using 18pt Times New Roman Bold Italic font
        c.addTitle("    Product Line Global Revenue", "Times New Roman Bold Italic", 18)

        ' Set the plotarea at (50, 55) with width 70 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() - 70, c.getHeight() - 90, c.linearGradientColor(0, 55, 0, _
            c.getHeight() - 35, &Hf0f6ff, &Ha0c0ff), -1, Chart.Transparent, &Hffffff, &Hffffff)

        ' 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)

        ' Set the axis stem to transparent
        c.xAxis().setColors(Chart.Transparent)
        c.yAxis().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("USD millions", "Arial Bold Italic", 10)

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

        ' Add 3 data series to the line layer
        layer.setXData(timeStamps)
        layer.addDataSet(data0, &Hff3333, "Alpha")
        layer.addDataSet(data1, &H008800, "Beta")
        layer.addDataSet(data2, &H3333cc, "Gamma")

        ' Assign the chart to the WinChartViewer
        winChartViewer1.Chart = c

    End Sub

    '
    ' Draw track cursor when mouse is moving over plotarea
    '
    Private Sub winChartViewer1_MouseMovePlotArea(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.MouseEventArgs) Handles winChartViewer1.MouseMovePlotArea

        Dim viewer As WinChartViewer = sender
        trackLineLabel(viewer.Chart, viewer.PlotAreaMouseX)
        viewer.updateDisplay()

        ' Hide the track cursor when the mouse leaves the plot area
        viewer.removeDynamicLayer("MouseLeavePlotArea")

    End Sub

    '
    ' Draw track line with data labels
    '
    Private Sub trackLineLabel(c As XYChart, mouseX As Integer)

        ' Clear the current dynamic layer and get the DrawArea object to draw on it.
        Dim d As DrawArea = c.initDynamicLayer()

        ' The plot area object
        Dim plotArea As PlotArea = c.getPlotArea()

        ' Get the data x-value that is nearest to the mouse, and find its pixel coordinate.
        Dim xValue As Double = c.getNearestXValue(mouseX)
        Dim xCoor As Integer = c.getXCoor(xValue)

        ' Draw a vertical track line at the x-position
        d.vline(plotArea.getTopY(), plotArea.getBottomY(), xCoor, d.dashLineColor(&H000000, &H0101))

        ' Draw a label on the x-axis to show the track line position.
        Dim xlabel As String = "<*font,bgColor=000000*> " & c.xAxis().getFormattedLabel(xValue, _
            "mmm dd, yyyy") & " <*/font*>"
        Dim t As TTFText = d.text(xlabel, "Arial Bold", 8)

        ' Restrict the x-pixel position of the label to make sure it stays inside the chart image.
        Dim xLabelPos As Integer = Math.Max(0, Math.Min(xCoor - t.getWidth() / 2, c.getWidth() - t.getWidth( _
            )))
        t.draw(xLabelPos, plotArea.getBottomY() + 6, &Hffffff)

        ' Iterate through all layers to draw the data labels
        For i As Integer = 0 To c.getLayerCount() - 1
            Dim layer As Layer = c.getLayerByZ(i)

            ' The data array index of the x-value
            Dim xIndex As Integer = layer.getXIndexOf(xValue)

            ' Iterate through all the data sets in the layer
            For j As Integer = 0 To layer.getDataSetCount() - 1
                Dim dataSet As ChartDirector.DataSet = layer.getDataSetByZ(j)

                ' Get the color and position of the data label
                Dim color As Integer = dataSet.getDataColor()
                Dim yCoor As Integer = c.getYCoor(dataSet.getPosition(xIndex), dataSet.getUseYAxis())

                ' Draw a track dot with a label next to it for visible data points in the plot area
                If (yCoor >= plotArea.getTopY()) And (yCoor <= plotArea.getBottomY()) And (color <> _
                    Chart.Transparent) Then

                    d.circle(xCoor, yCoor, 4, 4, color, color)

                    Dim label As String = "<*font,bgColor=" & Hex(color) & "*> " & c.formatValue( _
                        dataSet.getValue(xIndex), "{value|P4}") & " <*/font*>"
                    t = d.text(label, "Arial Bold", 8)

                    ' Draw the label on the right side of the dot if the mouse is on the left side the chart,
                    ' and vice versa. This ensures the label will not go outside the chart image.
                    If xCoor <= (plotArea.getLeftX() + plotArea.getRightX()) / 2 Then
                        t.draw(xCoor + 5, yCoor, &Hffffff, Chart.Left)
                    Else
                        t.draw(xCoor - 5, yCoor, &Hffffff, Chart.Right)
                    End If
                End If
            Next
        Next

    End Sub

End Class

[WPF - XAML] NetWPFCharts\TrackLabelWindow.xaml
<Window x:Class="CSharpWPFDemo.TrackLabelWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:CSharpWPFDemo"
        mc:Ignorable="d"
        xmlns:ChartDirector="clr-namespace:ChartDirector;assembly=netchartdir" UseLayoutRounding="True"
        Title="Track Line with Data Labels" SizeToContent="WidthAndHeight" ResizeMode="NoResize" Loaded="Window_Loaded">
    <Grid>
        <ChartDirector:WPFChartViewer x:Name="WPFChartViewer1" Margin="5" MouseMovePlotArea="WPFChartViewer1_MouseMovePlotArea" />
    </Grid>
</Window>

[WPF - C#] NetWPFCharts\TrackLabelWindow.xaml.cs
using System;
using System.Collections;
using System.Windows;
using System.Windows.Input;
using ChartDirector;

namespace CSharpWPFDemo
{
    public partial class TrackLabelWindow : Window
    {
        public TrackLabelWindow()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            // Data for the chart as 3 random data series
            RanSeries r = new RanSeries(127);
            double[] data0 = r.getSeries(100, 100, -15, 15);
            double[] data1 = r.getSeries(100, 150, -15, 15);
            double[] data2 = r.getSeries(100, 200, -15, 15);
            DateTime[] timeStamps = r.getDateSeries(100, new DateTime(2011, 1, 1), 86400);

            // Create a XYChart object of size 640 x 400 pixels
            XYChart c = new XYChart(640, 400);

            // Add a title to the chart using 18pt Times New Roman Bold Italic font
            c.addTitle("    Product Line Global Revenue", "Times New Roman Bold Italic", 18);

            // Set the plotarea at (50, 55) with width 70 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() - 70, 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);

            // Set the axis stem to transparent
            c.xAxis().setColors(Chart.Transparent);
            c.yAxis().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("USD millions", "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 3 data series to the line layer
            layer.setXData(timeStamps);
            layer.addDataSet(data0, 0xff3333, "Alpha");
            layer.addDataSet(data1, 0x008800, "Beta");
            layer.addDataSet(data2, 0x3333cc, "Gamma");

            // Assign the chart to the WPFChartViewer
            WPFChartViewer1.Chart = c;
        }

        //
        // Draw track cursor when mouse is moving over plotarea
        //
        private void WPFChartViewer1_MouseMovePlotArea(object sender, MouseEventArgs e)
        {
            WPFChartViewer viewer = (WPFChartViewer)sender;
            trackLineLabel((XYChart)viewer.Chart, viewer.PlotAreaMouseX);
            viewer.updateDisplay();

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

        //
        // Draw track line with data labels
        //
        private void trackLineLabel(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);

            // Draw a vertical track line at the x-position
            d.vline(plotArea.getTopY(), plotArea.getBottomY(), xCoor, d.dashLineColor(0x000000, 0x0101));

            // Draw a label on the x-axis to show the track line position.
            string xlabel = "<*font,bgColor=000000*> " + c.xAxis().getFormattedLabel(xValue, "mmm dd, yyyy") +
                " <*/font*>";
            TTFText t = d.text(xlabel, "Arial Bold", 8);

            // Restrict the x-pixel position of the label to make sure it stays inside the chart image.
            int xLabelPos = Math.Max(0, Math.Min(xCoor - t.getWidth() / 2, c.getWidth() - t.getWidth()));
            t.draw(xLabelPos, plotArea.getBottomY() + 6, 0xffffff);

            // Iterate through all layers to draw the data labels
            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);

                    // Get the color and position of the data label
                    int color = dataSet.getDataColor();
                    int yCoor = c.getYCoor(dataSet.getPosition(xIndex), dataSet.getUseYAxis());

                    // Draw a track dot with a label next to it for visible data points in the plot area
                    if ((yCoor >= plotArea.getTopY()) && (yCoor <= plotArea.getBottomY()) && (color !=
                        Chart.Transparent)) {

                        d.circle(xCoor, yCoor, 4, 4, color, color);

                        string label = "<*font,bgColor=" + color.ToString("x") + "*> " + c.formatValue(
                            dataSet.getValue(xIndex), "{value|P4}") + " <*/font*>";
                        t = d.text(label, "Arial Bold", 8);

                        // Draw the label on the right side of the dot if the mouse is on the left side the
                        // chart, and vice versa. This ensures the label will not go outside the chart image.
                        if (xCoor <= (plotArea.getLeftX() + plotArea.getRightX()) / 2) {
                            t.draw(xCoor + 5, yCoor, 0xffffff, Chart.Left);
                        } else {
                            t.draw(xCoor - 5, yCoor, 0xffffff, Chart.Right);
                        }
                    }
                }
            }
        }
    }
}