ChartDirector是一個(gè)非常容易上手的Web圖表控件，參照它的JSP例子，簡單修改一下就可以創(chuàng)建一系列基于Web的圖表。下面跟大家分享用ChartDirector(C++)繪制的可滾動(dòng)和縮放的圖表。下面為大家奉上了源代碼，首先解釋一下代碼的組成部分：

• 初始化：將數(shù)據(jù)加載到內(nèi)存，然后初始化CChartViewer；
• CVN_ViewPortChanged消息處理器：用于更新圖表和圖像映射；
• drawChart：這是創(chuàng)建圖表的核心部分。首先用ViewPortManager.getValueAtViewPort獲取可見數(shù)據(jù)范圍，然后獲取數(shù)據(jù)范圍中的值。最后用ViewPortManager.syncDateAxisWithViewPort將X軸配置與視圖端口同步。

下面是繪制一個(gè)可滾動(dòng)和縮放圖表的主要源代碼，完整代碼請參考ChartDirector MFC項(xiàng)目中的"mfcdemo/simplezoomscroll"

[File: mfcdemo/simplezoomscroll/simplezoomscrollDlg.cpp]

// simplezoomscrollDlg.cpp : implementation file
//

#include "stdafx.h"
#include "simplezoomscroll.h"
#include "simplezoomscrollDlg.h"
#include "chartdir.h"
#include <math.h>

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

/////////////////////////////////////////////////////////////////////////////
// CSimplezoomscrollDlg dialog

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

//
// Destructor
//
CSimplezoomscrollDlg::~CSimplezoomscrollDlg()
{
    delete m_ranSeries;
    delete m_ChartViewer.getChart();
}

void CSimplezoomscrollDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    //{{AFX_DATA_MAP(CSimplezoomscrollDlg)
    DDX_Control(pDX, IDC_PointerPB, m_PointerPB);
    DDX_Control(pDX, IDC_ChartViewer, m_ChartViewer);
    //}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CSimplezoomscrollDlg, CDialog)
    //{{AFX_MSG_MAP(CSimplezoomscrollDlg)
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    ON_WM_DESTROY()
    ON_BN_CLICKED(IDC_PointerPB, OnPointerPB)
    ON_BN_CLICKED(IDC_ZoomInPB, OnZoomInPB)
    ON_BN_CLICKED(IDC_ZoomOutPB, OnZoomOutPB)
    ON_CONTROL(CVN_ViewPortChanged, IDC_ChartViewer, OnViewPortChanged)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CSimplezoomscrollDlg message handlers

//
// Initialization
//
BOOL CSimplezoomscrollDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

    // *** code automatically generated by VC++ MFC AppWizard ***
    // 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
    
    // Load icons to mouse usage buttons
    loadButtonIcon(IDC_PointerPB, IDI_PointerPB, 100, 20);  
    loadButtonIcon(IDC_ZoomInPB, IDI_ZoomInPB, 100, 20);    
    loadButtonIcon(IDC_ZoomOutPB, IDI_ZoomOutPB, 100, 20);

    //
    // Initialize member variables
    //
    m_extBgColor = getDefaultBgColor();     // Default background color

    // Load the data
    loadData();

    // Initialize the CChartViewer
    initChartViewer(&m_ChartViewer);

    // Trigger the ViewPortChanged event to draw the chart
    m_ChartViewer.updateViewPort(true, true);
    return TRUE;
}

// *** code automatically generated by VC++ MFC AppWizard ***
// 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 CSimplezoomscrollDlg::OnPaint() 
{
    if (IsIconic())
    {
        CPaintDC dc(this); // device context for painting

        SendMessage(WM_ICONERASEBKGND, (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();
    }
}

// *** code automatically generated by VC++ MFC AppWizard ***
// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CSimplezoomscrollDlg::OnQueryDragIcon()
{
    return (HCURSOR) m_hIcon;
}

//
// User clicks on the Pointer pushbutton
//
void CSimplezoomscrollDlg::OnPointerPB() 
{
    m_ChartViewer.setMouseUsage(Chart::MouseUsageScroll);   
}

//
// User clicks on the Zoom In pushbutton
//
void CSimplezoomscrollDlg::OnZoomInPB() 
{
    m_ChartViewer.setMouseUsage(Chart::MouseUsageZoomIn);   
}

//
// User clicks on the Zoom Out pushbutton
//
void CSimplezoomscrollDlg::OnZoomOutPB() 
{
    m_ChartViewer.setMouseUsage(Chart::MouseUsageZoomOut);  
}

//
// The ViewPortChanged event handler. This event occurs if the user scrolls or zooms in or 
// out the chart by dragging or clicking on the chart. It can also be triggered by calling
// CChartViewer.updateViewPort.
//
void CSimplezoomscrollDlg::OnViewPortChanged()
{
    if (m_ChartViewer.needUpdateChart())
        drawChart(&m_ChartViewer);
    if (m_ChartViewer.needUpdateImageMap())
        updateImageMap(&m_ChartViewer);
}

/////////////////////////////////////////////////////////////////////////////
// CSimplezoomscrollDlg methods

//
// Load the data
//
void CSimplezoomscrollDlg::loadData()
{
    // In this example, we just use random numbers as data.
    m_ranSeries = new RanSeries(127);
    m_timeStamps = m_ranSeries->getDateSeries(1827, Chart::chartTime(2007, 1, 1), 86400);
    m_dataSeriesA = m_ranSeries->getSeries(1827, 150, -10, 10);
    m_dataSeriesB = m_ranSeries->getSeries(1827, 200, -10, 10);
    m_dataSeriesC = m_ranSeries->getSeries(1827, 250, -8, 8);
}

//
// Initialize the CChartViewer 
//
void CSimplezoomscrollDlg::initChartViewer(CChartViewer *viewer)
{
    // Set the full x range to be the duration of the data
    viewer->setFullRange("x", m_timeStamps[0], m_timeStamps[m_timeStamps.len - 1]);

    // Initialize the view port to show the latest 20% of the time range
    viewer->setViewPortWidth(0.2);
    viewer->setViewPortLeft(1 - viewer->getViewPortWidth());

    // Set the maximum zoom to 10 points
    viewer->setZoomInWidthLimit(10.0 / m_timeStamps.len);

    // Initially set the mouse to drag to scroll mode.
    m_PointerPB.SetCheck(1);
    viewer->setMouseUsage(Chart::MouseUsageScroll);
}

//
// Draw the chart and display it in the given viewer
//
void CSimplezoomscrollDlg::drawChart(CChartViewer *viewer)
{
    // Get the start date and end date that are visible on the chart.
    double viewPortStartDate = viewer->getValueAtViewPort("x", viewer->getViewPortLeft());
    double viewPortEndDate = viewer->getValueAtViewPort("x", viewer->getViewPortLeft() +
        viewer->getViewPortWidth());

    // Get the array indexes that corresponds to the visible start and end dates
    int startIndex = (int)floor(Chart::bSearch(m_timeStamps, viewPortStartDate));
    int endIndex = (int)ceil(Chart::bSearch(m_timeStamps, viewPortEndDate));
    int noOfPoints = endIndex - startIndex + 1;

    // Extract the part of the data array that are visible.
    DoubleArray viewPortTimeStamps = DoubleArray(m_timeStamps.data + startIndex, noOfPoints);
    DoubleArray viewPortDataSeriesA = DoubleArray(m_dataSeriesA.data + startIndex, noOfPoints);
    DoubleArray viewPortDataSeriesB = DoubleArray(m_dataSeriesB.data + startIndex, noOfPoints);
    DoubleArray viewPortDataSeriesC = DoubleArray(m_dataSeriesC.data + startIndex, noOfPoints);

    //
    // At this stage, we have extracted the visible data. We can use those data to plot the chart.
    //

    ///////////////////////////////////////////////////////////////////////////////////////
    // Configure overall chart appearance. 
    ///////////////////////////////////////////////////////////////////////////////////////

    // Create an XYChart object 600 x 300 pixels in size, with pale blue (0xf0f0ff) background,
    // black (000000) rounded border, 1 pixel raised effect.
    XYChart *c = new XYChart(600, 300, 0xf0f0ff, 0, 1);
    c->setRoundedFrame(m_extBgColor);

    // Set the plotarea at (52, 60) and of size 520 x 205 pixels. Use white (ffffff) background.
    // Enable both horizontal and vertical grids by setting their colors to grey (cccccc). Set
    // clipping mode to clip the data lines to the plot area.
    c->setPlotArea(52, 60, 520, 205, 0xffffff, -1, -1, 0xcccccc, 0xcccccc);
    
    // As the data can lie outside the plotarea in a zoomed chart, we need to enable clipping.
    c->setClipping();

    // Add a top title to the chart using 15 pts Times New Roman Bold Italic font, with a light blue
    // (ccccff) background, black (000000) border, and a glass like raised effect.
    c->addTitle("Simple Zooming and Scrolling", "timesbi.ttf", 15
        )->setBackground(0xccccff, 0x0, Chart::glassEffect());

    // Add a legend box at the top of the plot area with 9pts Arial Bold font with flow layout.
    c->addLegend(50, 33, false, "arialbd.ttf", 9)->setBackground(Chart::Transparent, Chart::Transparent);

    // Set axes width to 2 pixels
    c->yAxis()->setWidth(2);
    c->xAxis()->setWidth(2);

    // Add a title to the y-axis
    c->yAxis()->setTitle("Price (USD)", "arialbd.ttf", 9);

    ///////////////////////////////////////////////////////////////////////////////////////
    // Add data to chart
    ///////////////////////////////////////////////////////////////////////////////////////

    // 
    // In this example, we represent the data by lines. You may modify the code below to use other
    // representations (areas, scatter plot, etc).
    //

    // Add a line layer for the lines, using a line width of 2 pixels
    LineLayer *layer = c->addLineLayer();
    layer->setLineWidth(2);

    // In this demo, we do not have too many data points. In real code, the chart may contain a lot
    // of data points when fully zoomed out - much more than the number of horizontal pixels in this
    // plot area. So it is a good idea to use fast line mode.
    layer->setFastLineMode();

    // Now we add the 3 data series to a line layer, using the color red (ff0000), green
    // (00cc00) and blue (0000ff)
    layer->setXData(viewPortTimeStamps);
    layer->addDataSet(viewPortDataSeriesA, 0xff0000, "Product Alpha");
    layer->addDataSet(viewPortDataSeriesB, 0x00cc00, "Product Beta");
    layer->addDataSet(viewPortDataSeriesC, 0x0000ff, "Product Gamma");

    ///////////////////////////////////////////////////////////////////////////////////////
    // Configure axis scale and labelling
    ///////////////////////////////////////////////////////////////////////////////////////
    
    // Set the x-axis as a date/time axis with the scale according to the view port x range.
    viewer->syncDateAxisWithViewPort("x", c->xAxis());

    // In this demo, we rely on ChartDirector to auto-label the axis. We ask ChartDirector to ensure
    // the x-axis labels are at least 75 pixels apart to avoid too many labels.
    c->xAxis()->setTickDensity(75);

    ///////////////////////////////////////////////////////////////////////////////////////
    // Output the chart
    ///////////////////////////////////////////////////////////////////////////////////////

    delete viewer->getChart();
    viewer->setChart(c);
}

//
// Update the image map
//
void CSimplezoomscrollDlg::updateImageMap(CChartViewer *viewer)
{
    // Include tool tip for the chart
    if (0 == viewer->getImageMapHandler())
    {
        viewer->setImageMap(viewer->getChart()->getHTMLImageMap("", "",
            "title='[{dataSetName}] {x|mmm dd, yyyy}: USD {value|2}'"));
    }
}

/////////////////////////////////////////////////////////////////////////////
// General utilities

//
// Get the default background color
//
int CSimplezoomscrollDlg::getDefaultBgColor()
{
    LOGBRUSH LogBrush; 
    HBRUSH hBrush = (HBRUSH)SendMessage(WM_CTLCOLORDLG, (WPARAM)CClientDC(this).m_hDC, 
        (LPARAM)m_hWnd); 
    ::GetObject(hBrush, sizeof(LOGBRUSH), &LogBrush); 
    int ret = LogBrush.lbColor;
    return ((ret & 0xff) << 16) | (ret & 0xff00) | ((ret & 0xff0000) >> 16);
}

//
// Load an icon resource into a button
//
void CSimplezoomscrollDlg::loadButtonIcon(int buttonId, int iconId, int width, int height)
{
    GetDlgItem(buttonId)->SendMessage(BM_SETIMAGE, IMAGE_ICON, (LPARAM)::LoadImage(
        AfxGetResourceHandle(), MAKEINTRESOURCE(iconId), IMAGE_ICON, width, height, 
        LR_DEFAULTCOLOR));  
}