ChartDirector 6.0 (C++ Edition)

Track Line with Legend (MFC)




NOTE: This section describes Track Line with Legend for MFC, and is available on the Windows edition of ChartDirector for C++ only. For QT, please refer to Track Line with Legend (QT).

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

The code first draws the chart, and sets the track cursor to the right side of the plot area. This ensures the chart initially has a legend that reflects the latest data values. In the CVN_MouseMovePlotArea message handler, the track cursor is updated to reflect the mouse position.

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

Source Code Listing

The following is the main source code of this demo. The complete MFC project is in "mfcdemo/tracklegend".

[File: mfcdemo/tracklegend/tracklegendDlg.cpp]
// tracklegendDlg.cpp : implementation file
//

#include "stdafx.h"
#include "tracklegend.h"
#include "tracklegendDlg.h"
#include "chartdir.h"
#include <vector>
#include <sstream>

using namespace std;

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// CtracklegendDlg dialog

CtracklegendDlg::CtracklegendDlg(CWnd* pParent /*=NULL*/)
    : CDialog(CtracklegendDlg::IDD, pParent)
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

CtracklegendDlg::~CtracklegendDlg()
{
    delete m_ChartViewer.getChart();
}

void CtracklegendDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    DDX_Control(pDX, IDC_ChartViewer, m_ChartViewer);
}

BEGIN_MESSAGE_MAP(CtracklegendDlg, CDialog)
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    ON_WM_ERASEBKGND()
    ON_CONTROL(CVN_MouseMovePlotArea, IDC_ChartViewer, OnMouseMovePlotArea)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()


// CtracklegendDlg message handlers

BOOL CtracklegendDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

    // Set the icon for this dialog.  The framework does this automatically
    //  when the application's main window is not a dialog
    SetIcon(m_hIcon, TRUE);            // Set big icon
    SetIcon(m_hIcon, FALSE);        // Set small icon

    drawChart(&m_ChartViewer);

    CRect winSize;
    m_ChartViewer.GetWindowRect(winSize);
    m_ChartViewer.MoveWindow(5, 5, winSize.Width(), winSize.Height());

    CalcWindowRect(&winSize, CWnd::adjustBorder);
    SetWindowPos(&wndTop, 0, 0, winSize.Width() + 10, winSize.Height() + 10, SWP_NOMOVE);
 
    return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CtracklegendDlg::OnPaint()
{
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // Center icon in client rectangle
        int cxIcon = GetSystemMetrics(SM_CXICON);
        int cyIcon = GetSystemMetrics(SM_CYICON);
        CRect rect;
        GetClientRect(&rect);
        int x = (rect.Width() - cxIcon + 1) / 2;
        int y = (rect.Height() - cyIcon + 1) / 2;

        // Draw the icon
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialog::OnPaint();
    }
}

// The system calls this function to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CtracklegendDlg::OnQueryDragIcon()
{
    return static_cast<HCURSOR>(m_hIcon);
}

//
// Handle the ON_WM_ERASEBKGND message to set background color
//
BOOL CtracklegendDlg::OnEraseBkgnd(CDC* pDC) 
{ 
    // Set brush to desired background color 
    CBrush backBrush(RGB(255, 255, 255)); 

    // Save old brush 
    CBrush* pOldBrush = pDC->SelectObject(&backBrush); 

    // Erase the area needed with the given background color
    CRect rect; 
    pDC->GetClipBox(&rect);
    pDC->PatBlt(rect.left, rect.top, rect.Width(), rect.Height(), PATCOPY); 

    // Restore old brush and exit
    pDC->SelectObject(pOldBrush); 
    return TRUE; 
} 

//
// Draw track cursor when mouse is moving over plotarea
//
void CtracklegendDlg::OnMouseMovePlotArea()
{
    trackLineLegend((XYChart *)m_ChartViewer.getChart(), m_ChartViewer.getPlotAreaMouseX());
    m_ChartViewer.updateDisplay();
}

/////////////////////////////////////////////////////////////////////////////
// CtracklegendDlg methods

//
// Draw the chart and display it in the given viewer
//
void CtracklegendDlg::drawChart(CChartViewer *viewer)
{
    // Data for the chart as 3 random data series
    RanSeries r(127);
    DoubleArray data0 = r.getSeries(100, 100, -15, 15);
    DoubleArray data1 = r.getSeries(100, 150, -15, 15);
    DoubleArray data2 = r.getSeries(100, 200, -15, 15);
    DoubleArray timeStamps = r.getDateSeries(100, Chart::chartTime(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 18 pts Times New Roman Bold Italic font
    c->addTitle("    Product Line Global Revenue", "timesbi.ttf", 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);

    // Set legend icon style to use line style icon, sized for 8pt font
    c->getLegend()->setLineStyleKey();
    c->getLegend()->setFontSize(8);

    // Set axis label style to 8pts Arial Bold
    c->xAxis()->setLabelStyle("arialbd.ttf", 8);
    c->yAxis()->setLabelStyle("arialbd.ttf", 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 10pts Arial Bold Italic font
    c->yAxis()->setTitle("USD millions", "arialbi.ttf", 10);

    // Add a line layer to the chart using a line width of 2 pixels.
    LineLayer *layer = c->addLineLayer();
    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");

    // Include track line with legend for the latest data values
    trackLineLegend(c, c->getPlotArea()->getRightX());

    // Assign the chart to the WinChartViewer
    viewer->setChart(c);
}

//
// Draw the track line with legend
//
void CtracklegendDlg::trackLineLegend(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));

    // Container to hold the legend entries
    vector<string> legendEntries;

    // 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) {
            DataSet *dataSet = layer->getDataSetByZ(j);

            // We are only interested in visible data sets with names
            const char *dataName = dataSet->getDataName();
            int color = dataSet->getDataColor();
            if (dataName && *dataName && (color != Chart::Transparent)) {
                // Build the legend entry, consist of the legend icon, name and data value.
                double dataValue = dataSet->getValue(xIndex);
                ostringstream legendEntry;
                legendEntry << "<*block*>" << dataSet->getLegendIcon() << " " << dataName << ": " <<
                    ((dataValue == Chart::NoValue) ? "N/A" : c->formatValue(dataValue, "{value|P4}"))
                    << "<*/*>";
                legendEntries.push_back(legendEntry.str());

                // Draw a track dot for data points within the plot area
                int yCoor = c->getYCoor(dataSet->getPosition(xIndex), dataSet->getUseYAxis());
                if ((yCoor >= plotArea->getTopY()) && (yCoor <= plotArea->getBottomY())) {
                    d->circle(xCoor, yCoor, 4, 4, color, color);
                }
            }
        }
    }

    // Create the legend by joining the legend entries
    ostringstream legendText;
    legendText << "<*block,maxWidth=" << plotArea->getWidth() << "*><*block*><*font=arialbd.ttf*>["
        << c->xAxis()->getFormattedLabel(xValue, "mmm dd, yyyy") << "]<*/*>";
    for (int i = ((int)legendEntries.size()) - 1; i >= 0; --i)
        legendText << "        " << legendEntries[i];
    
    // Display the legend on the top of the plot area
    TTFText *t = d->text(legendText.str().c_str(), "arial.ttf", 8);
    t->draw(plotArea->getLeftX() + 5, plotArea->getTopY() - 3, 0x000000, Chart::BottomLeft);
    t->destroy();
}