OpenCV系列1-简单高效：MFC显示图片、播放视频

先看图：
拉伸显示

居中显示

原始大小显示

显示视频：

实现图片显示，只需要两句话：

只需要包含一个h文件：

调整显示方式：

下面是CvImgCtrl.h的源代码，复制保存下来即可用，或者也可以下载demo，不要积分
控件采用的是双缓冲绘图，显示效率很高，不会闪烁，支持视频、图片的显示

/************************************************************************/
/*                              OpenCV MFC图像显示控件 v1.0
/*    该控件很容易集成到mfc中显示，具体用法见demo：
/*                                                                               Wish: 512690069
/*                                                                      2016年4月6日 15:28:58 
/************************************************************************/

#pragma once

#include <cv.h>
#include <highgui.h>
#include <afxwin.h>

//自定义消息基础值
#define MsgBase                 (WM_USER + 0xA0)
#define MsgLBDown           (MsgBase + 0)                   //鼠标左键被按下的消息
#define MsgLBUp                 (MsgBase + 1)                   //左键抬起来
#define MsgRBDown           (MsgBase + 2)                   //右键按下
#define MsgMove             (MsgBase + 3)                   //鼠标移动

#define MsgMBDown           (MsgBase + 4)                   //中键按下
#define MsgMBUp             (MsgBase + 5)                   //中键抬起

#define MsgKeyDown          (MsgBase + 6)                   //按下某个键盘按键  
#define MsgDragFile             (MsgBase + 7)                   //拖动文件到控件上去的时候

#define MsgVideoStart           (MsgBase + 8)                   //视频开始的时候
#define MsgVideoOver            (MsgBase + 9)                   //视频结束了


//得到一帧视频画面了，具体看demo
//1、在dlg的头文件中写：afx_msg LRESULT onFrame(WPARAM wp, LPARAM lp);声明
//2、在dlg的BEGIN_MESSAGE_MAP里面写：ON_MESSAGE(MsgVideoFrame, onFrame)
//3、在dlg的cpp中写：
/*
LRESULT CdemoDlg::onFrame(WPARAM wp, LPARAM lp){
    Mat frame((IplImage*)lp, false);
    flip(frame, frame, -1);
    //这里就是在处理每一帧的图像了，类似的MsgVideoPreDisplay消息也是这么来的
    return 0;
}
*/
#define MsgVideoFrame           (MsgBase + 0x0A)            
#define MsgVideoPreDisplay  (MsgBase + 0x0B)        //视频一帧画面准备显示了，他会在MsgVideoFrame之后

//控件被单击消息
#define MsgClick                            (MsgBase + 0x0C)

//内部消息，内部使用，不需要理会
#define InnerMsgBase                    (MsgBase + 0xF0)                    //基本消息起点
#define InnerMsgVideoFrame      (InnerMsgBase + 0)              //接受到一帧画面

//图像显示控件
class CvImgCtrl : public CWnd
{
    DECLARE_DYNAMIC(CvImgCtrl)

public:
    //视图缩放类型
    enum ResizeType
    {
        ResizeType_Raw,                 //原始大小，以左上角为准，图像多大就多大，不做缩放
        ResizeType_CenterResize,        //居中缩放，图像宽高等比例，画面居中
        ResizeType_Tensile              //拉伸，宽高拉伸到控件一样大
    };

    //视频播放的状态
    enum VideoState{
        VideoState_Stop,                    //视频停止了
        VideoState_Playing,             //视频播放中
        VideoState_Pause                    //视频暂停了
    };

public:
    CvImgCtrl();
    virtual ~CvImgCtrl();

    //链接到对话框上的控件，链接过后，就被这个类接管了，他会负责将画面绘制到控件上去
    //idd：控件的id
    //parent：父控件的指针，比如在dialog里面，给this就行了
    BOOL linkDlgItem(UINT idd, CWnd* parent);

    //创建一个控件，如果需要动态创建，就调用这个创建函数，而不是CWnd的创建函数
    //pParent：父级的指针，一般给dialog的this指针就好了
    //rcPos：控件所在位置，可以直接给CRect()也行，然后在OnSize里边调整宽高，或者给指定值也行
    //autoDelete：如果CvImgCtrl* m_show，这种，指针，采用new的方式得到的控件，而不是实体变量，那么当这个参数给true的时候，控件销毁时
    //                    会自己回收内存（delete this），也就是你就不用手动的去delete他了
    //resizeType：缩放方式，当显示图像和窗口大小不一致时，该如何缩放，有3种方式，看枚举类型ResizeType的备注
    //defaultColor：默认颜色，即背景默认色，比如居中显示的时候，四周会留空，该是什么颜色，或者刚创建完毕时是什么颜色等
    bool create(CWnd* pParent, CRect rcPos, bool autoDelete = false, ResizeType resizeType = ResizeType_Raw, CvScalar defaultColor = cvScalarAll(255));

    //开始视频，这个控件内置了VideoCapture，所以这里直接可以调用openVideo来打开视频
    //file：视频文件路径，直接是VideoCapture.open，如果失败格式不支持，那就去看VideoCapture
    //waitTime：延迟时间，每一帧画面需要延迟的时间，单位毫秒，如果不延迟，画面会很快的，当然你可以改改成从VideoCapture中获取的
    bool openVideo(const char* file, unsigned int waitTime = 30);

    //开始视频摄像头，这个控件内置了VideoCapture，所以这里直接可以调用openVideo来打开视频
    //cameraIndex：摄像头索引，一样是VideoCapture的open函数，opencv默认-1会弹出选择视频对话框，0-n是你电脑n个摄像头的序号，他们有固定顺序的
    //waitTime：延迟时间，每一帧画面需要延迟的时间，单位毫秒，如果不延迟，画面会很快的，当然你可以改改成从VideoCapture中获取的
    bool openVideo(int cameraIndex = 0, unsigned int waitTime = 30);

    //暂停视频
    void pauseVideo(); 

    //继续视频
    void resumeVideo();

    //关闭视频
    void closeVideo();

    //设置图像，设置后控件会刷新显示，会执行onUpdateImage，允许你设置任意图像，内部会自动调整
    //如果设置的图像是相同大小、相同通道的图像，则只会进行copy，所以效率是杠杠的
    void setImage(const cv::Mat img){setImage(&IplImage(img));}

    //设置图像ipl方式，设置后控件会刷新显示，会执行onUpdateImage
    void setImage(const IplImage* img);

    //获取当前图像
    cv::Mat getImageMat(){return cv::Mat(m_img, false);}

    //获取当前图像
    IplImage* getImage(){return m_img;}

    //更新显示图像，如果你通过getImageMat得到的Mat或者IplImage，你修改了他，那么请使用onUpdateImage来刷新画面应用到控件上
    void onUpateImage();

    //获取显示图像，显示图像即跟控件一样大小的那个图像，随着控件大小改变而改变
    IplImage* getDisplayImage(){return m_imgResize;}

    //获取显示图像Mat
    cv::Mat getDisplayImageMat(){return cv::Mat(m_imgResize, false);}

    //更新显示图像，当你通过getDisplayImage获取到的图像，并修改了他，那么请使用这个函数来刷新应用到画面上
    void onUpdateDisplayImage();

    //设置缩放方式，共3种方式，见ResizeType的定义上写的备注，设置后立马生效并刷新
    void setResizeType(ResizeType rt){m_rt = rt; onUpateImage();}

    //设置数据，存一个int，以备特殊时候使用，比如要存什么id之类的，指针之类的
    void setData(int data){m_saveData = data;}
    int getData(){return m_saveData;}

    //获取视频捕获器
    cv::VideoCapture* getVideoCapture(){return &m_videoCapture;}

    //返回当前播放视频状态
    VideoState getVideoState(){return m_videoState;}

private:
    //设置图像，只是设置图像，不会显示到控件上去
    void _onlySetImage(const IplImage* img);

    //启动视频，device_or_file，如果给定-1或者0-1024以内的数字，则认为是camera
    //否则认为是文件路径，waittime则是帧延迟时间
    bool _startVideo(const void* device_or_file, unsigned int waitTime = 30);

    //重画image到displayimage（即resizeimage）
    void redrawResize();

    //清空显示的那个图像
    void voidResize();

    //通知父亲，默认wp是this
    LRESULT notifyParent(UINT msg, LPARAM lp = 0);

private:
    cv::VideoCapture m_videoCapture;
    VideoState m_videoState;
    int m_videoWaitTime;  
    unsigned int m_lastdownTime;
    int m_saveData;
    IplImage* m_img;
    IplImage* m_imgResize;
    BITMAPINFO m_bmpHeader;
    bool m_autoDelete;
    CvScalar m_defaultColor;
    ResizeType m_rt;
    CRITICAL_SECTION m_resizeCS;

protected:
    DECLARE_MESSAGE_MAP()
public:
    afx_msg void OnSize(UINT nType, int cx, int cy);
    afx_msg void OnDestroy();
    afx_msg BOOL OnEraseBkgnd(CDC* pDC);
    afx_msg void OnPaint();
    afx_msg void OnNcDestroy();
    afx_msg void OnMouseMove(UINT nFlags, CPoint point);
    afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
    afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
    afx_msg void OnRButtonDown(UINT nFlags, CPoint point);
    afx_msg LRESULT OnNcHitTest(CPoint point);
    afx_msg void OnMButtonDown(UINT nFlags, CPoint point);
    afx_msg void OnMButtonUp(UINT nFlags, CPoint point);
    afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);
    afx_msg void OnDropFiles(HDROP hDropInfo);

    afx_msg LRESULT OnVideoFrame(WPARAM wp, LPARAM lp);
};


#define BEGIN_MESSAGE_MAP_EX(class_name)                \
    PTM_WARNING_DISABLE                                                     inline const AFX_MSGMAP* class_name::GetMessageMap() const  {return GetThisMessageMap();}                inline const AFX_MSGMAP* PASCAL class_name::GetThisMessageMap()     {typedef class_name ThisClass;                              typedef CWnd TheBaseClass;                              static const AFX_MSGMAP_ENTRY _messageEntries[] = {

#define IMPLEMENT_DYNAMIC_EX(class_name, super_class)           \
AFX_COMDAT const CRuntimeClass class_name::class##class_name = {    \
#class_name, sizeof(class class_name), 0xFFFF, NULL,                        \
((CRuntimeClass*)(&super_class::class##super_class)), NULL, NULL };     \
inline CRuntimeClass* class_name::GetRuntimeClass() const { return RUNTIME_CLASS(class_name); }

IMPLEMENT_DYNAMIC_EX(CvImgCtrl, CWnd)

inline static IplImage imgOfROI(const IplImage* img, CvRect roi, bool invalidROI=false)
{
    IplImage ret = *img;
    int imgWidth = img->roi != 0 && !invalidROI ? img->roi->width : img->width;
    int imgHeight = img->roi != 0 && !invalidROI ? img->roi->height : img->height;
    ret.roi = 0;

    if(roi.x >= imgWidth || roi.y >= imgHeight){
        ret.width = 0;
        ret.height = 0;
        ret.imageData = 0;
        return ret;
    }

    //区域裁剪
    if(roi.x < 0){
        roi.width += roi.x;
        roi.x = 0;
    }

    if(roi.y < 0) {
        roi.height += roi.y;
        roi.y = 0;
    }

    if(roi.x + roi.width > imgWidth)        roi.width = imgWidth - roi.x;
    if(roi.y + roi.height > imgHeight)      roi.height = imgHeight - roi.y;

    CV_Assert(roi.width > 0 && roi.height > 0);
    ret.width = roi.width;
    ret.height = roi.height;
    ret.imageSize = ret.height * ret.widthStep;
    ret.imageDataOrigin = 0;

    if (!invalidROI && img->roi != 0)
        ret.imageData = img->imageData + (img->roi->xOffset + roi.x) * img->nChannels * (img->depth & ~IPL_DEPTH_SIGN) / 8 + (img->roi->yOffset + roi.y) * img->widthStep;
    else
        ret.imageData = img->imageData + roi.x * img->nChannels * (img->depth & ~IPL_DEPTH_SIGN) / 8 + roi.y * img->widthStep;

    return ret;
}

inline static void doEvent(unsigned int waitMS = -1){
    MSG msg;
    unsigned int time = GetTickCount();

    while(GetTickCount() - time < waitMS){
        while(GetTickCount() - time < waitMS && PeekMessage(&msg, 0, 0, 0, PM_REMOVE)){
            if(msg.message == WM_QUIT)
                break;

            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
}

#define min(a,b) (((a) < (b)) ? (a) : (b))

inline CvImgCtrl::CvImgCtrl(){
    memset(&m_bmpHeader, 0, sizeof(m_bmpHeader));
    m_bmpHeader.bmiHeader.biSize = sizeof(m_bmpHeader);
    m_bmpHeader.bmiHeader.biXPelsPerMeter = 72;
    m_bmpHeader.bmiHeader.biYPelsPerMeter = 72;
    m_bmpHeader.bmiHeader.biPlanes = 1;
    m_imgResize = 0;
    m_img = 0;
    m_rt = ResizeType_Tensile;
    m_autoDelete = false;
    m_videoState = VideoState_Stop;
    m_defaultColor = cvScalarAll(255);
    InitializeCriticalSection(&m_resizeCS);
}

inline CvImgCtrl::~CvImgCtrl(){
    DeleteCriticalSection(&m_resizeCS);
}

BEGIN_MESSAGE_MAP_EX(CvImgCtrl)
    ON_WM_SIZE()
    ON_WM_DESTROY()
    ON_WM_ERASEBKGND()
    ON_WM_PAINT()
    ON_WM_NCDESTROY()
    ON_WM_MOUSEMOVE()
    ON_WM_LBUTTONDOWN()
    ON_WM_LBUTTONUP()
    ON_WM_NCHITTEST()
    ON_WM_RBUTTONDOWN()
    ON_WM_MBUTTONDOWN()
    ON_WM_MBUTTONUP()
    ON_WM_KEYDOWN()
    ON_WM_DROPFILES()
    ON_MESSAGE(InnerMsgVideoFrame, OnVideoFrame)
END_MESSAGE_MAP()

inline bool CvImgCtrl::openVideo(const char* file, unsigned int waitTime){
    return _startVideo(file, waitTime);
}

inline void CvImgCtrl::pauseVideo(){
    if(m_videoState == VideoState_Playing)
        m_videoState = VideoState_Pause;
}

inline bool CvImgCtrl::openVideo(int cameraIndex, unsigned int waitTime){
    return _startVideo((const void*)cameraIndex, waitTime);
}

inline void CvImgCtrl::resumeVideo(){
    if(m_videoState == VideoState_Pause){
        m_videoState = VideoState_Playing;
        PostMessage(InnerMsgVideoFrame, 0, 0);
    }
}

inline void CvImgCtrl::closeVideo(){
    m_videoState = VideoState_Stop;
    if(m_videoCapture.isOpened())
        m_videoCapture.release();
}

inline bool CvImgCtrl::_startVideo(const void* device_or_file, unsigned int waitTime){
    if(!::IsWindow(m_hWnd)) return false;

    int dof = (int)device_or_file;
    if(m_videoCapture.isOpened())
        m_videoCapture.release();

    bool success = false;
    const int max_count_of_device_index = 1024;
    const char* file = (const char*)device_or_file;
    const int device_index = (int)device_or_file;
    m_videoWaitTime = waitTime;

    if(dof == -1 || dof >= 0 && dof <= max_count_of_device_index)
        success = m_videoCapture.open(device_index);
    else
        success = m_videoCapture.open(file);

    m_videoState = success ? VideoState_Playing : VideoState_Stop;
    if(success) {
        cv::Mat frame;
        m_videoCapture >> frame;
        if(!frame.empty()){
            _onlySetImage(&IplImage(frame));
            notifyParent(MsgVideoStart, (LPARAM)device_or_file);
            notifyParent(MsgVideoFrame, (LPARAM)m_img);

            if (m_imgResize != 0){
                redrawResize();
                notifyParent(MsgVideoPreDisplay, (LPARAM)m_imgResize);

                this->onUpdateDisplayImage();
            }

            if(m_videoState == VideoState_Playing)
                PostMessage(InnerMsgVideoFrame, 0, 0);
        }else{
            success = false;
        }
    }
    m_videoState = success ? VideoState_Playing : VideoState_Stop;
    return success;
}

inline LRESULT CvImgCtrl::notifyParent(UINT msg, LPARAM lp){
    return ::SendMessage(GetParent()->m_hWnd, msg, (WPARAM)this, lp);
}

inline LRESULT CvImgCtrl::OnVideoFrame(WPARAM wp, LPARAM lp){
    if(m_videoState == VideoState_Playing){
        bool grab = m_videoCapture.grab();
        bool retrieve = grab && m_videoCapture.retrieve(cv::Mat(m_img, false));

        if(retrieve){
            notifyParent(MsgVideoFrame, (LPARAM)m_img);

            if (m_imgResize != 0){
                redrawResize();
                notifyParent(MsgVideoPreDisplay, (LPARAM)m_imgResize);

                this->onUpdateDisplayImage();
            }

            if(m_videoState == VideoState_Playing){
                doEvent(m_videoWaitTime);
                PostMessage(InnerMsgVideoFrame, wp, lp);
            }
        }else{
            notifyParent(MsgVideoOver);
            m_videoState = VideoState_Stop;
        }
    }
    return 0;
}

inline bool CvImgCtrl::create(
    CWnd* pParent, 
    CRect rcPos, 
    bool autoDelete /*= false*/,
    ResizeType rt /*= _ResizeType_Non*/, 
    CvScalar defaultColor /*= cvScalarAll(255)*/){

        m_defaultColor = defaultColor;
        m_autoDelete = autoDelete;
        m_rt = rt;
    return CWnd::Create(_T("Static"), 0, WS_OVERLAPPED | WS_CHILD | WS_VISIBLE, rcPos, pParent, 0, 0) != 0;
}

inline void CvImgCtrl::redrawResize(){
    if(m_imgResize == 0 || m_img == 0 || m_img->width * m_img->height == 0)
        return;

    EnterCriticalSection(&m_resizeCS);
    switch(m_rt)    {
    case ResizeType_Tensile:    {
            if(m_img->nChannels != 3){
                IplImage* re = cvCreateImage(cvGetSize(m_img), 8, 3);
                cvCvtColor(m_img, re, CV_GRAY2BGR);
                cvResize(re, m_imgResize);
                cvReleaseImage(&re);
            }
            else
                cvResize(m_img, m_imgResize);
        }
        break;

    case ResizeType_Raw: {
            voidResize();
            CvRect roi = {0, 0, min(m_img->width, m_imgResize->width), min(m_img->height, m_imgResize->height)};
            if(m_img->nChannels != 3)
                cvCvtColor(&imgOfROI(m_img, roi), &imgOfROI(m_imgResize, roi), CV_GRAY2BGR);
            else
                cvCopy(&imgOfROI(m_img, roi), &imgOfROI(m_imgResize, roi));
        }
        break;

    case ResizeType_CenterResize: {
            voidResize();
            int nw = m_imgResize->width;
            int nh = int(m_imgResize->width / (double)m_img->width * m_img->height);

            if (nh > m_imgResize->height)   {
                nh = m_imgResize->height;
                nw = int(m_imgResize->height / (double)m_img->height * m_img->width);
            }

            cvSetImageROI(m_imgResize, cvRect((m_imgResize->width - nw) / 2, (m_imgResize->height - nh) / 2, nw, nh));
            if(m_img->nChannels != 3){
                IplImage* re = cvCreateImage(cvGetSize(m_img), 8, 3);
                cvCvtColor(m_img, re, CV_GRAY2BGR);
                cvResize(re, m_imgResize);
                cvReleaseImage(&re);
            }
            else
                cvResize(m_img, m_imgResize);
            cvResetImageROI(m_imgResize);
        }
        break;
    }
    LeaveCriticalSection(&m_resizeCS);
}

inline void CvImgCtrl::onUpateImage(){
    if (m_imgResize != 0 && ::IsWindow(m_hWnd)){
        redrawResize();
        this->onUpdateDisplayImage();
    }
}

inline void CvImgCtrl::voidResize(){
    cvSet(m_imgResize, m_defaultColor);
}

inline BOOL CvImgCtrl::linkDlgItem(UINT idd, CWnd* parent){
    BOOL r = CWnd::SubclassDlgItem(idd, parent);
    if(r){
        CRect rc;
        GetWindowRect(&rc);

        OnSize(0, rc.Width(), rc.Height());
    }
    return r;
}

inline void CvImgCtrl::OnSize(UINT nType, int cx, int cy){
    if (cx < 1 || cy < 1){
        CWnd::OnSize(nType, cx, cy);
        return;
    }

    EnterCriticalSection(&m_resizeCS);
    cvReleaseImage(&m_imgResize);
    m_imgResize = cvCreateImage(cvSize(cx, cy), 8, 3);
    LeaveCriticalSection(&m_resizeCS);

    if(m_img != 0)
        redrawResize();
    else
        voidResize();

    m_bmpHeader.bmiHeader.biBitCount = m_imgResize->nChannels * m_imgResize->depth;
    m_bmpHeader.bmiHeader.biHeight = -m_imgResize->height;
    m_bmpHeader.bmiHeader.biWidth = m_imgResize->width;
    m_bmpHeader.bmiHeader.biSizeImage = m_imgResize->imageSize;
    this->onUpdateDisplayImage();
}

inline void CvImgCtrl::_onlySetImage(const IplImage* img){
    if (img == 0)   {
        if (m_img != 0)
            cvReleaseImage(&m_img);

        if (m_imgResize != 0)
            voidResize();

        return;
    }

    if (m_img == 0){
        m_img = (IplImage*)cvClone(img);
    }
    else{
        if (
            m_img->width != img->width || 
            m_img->height != img->height || 
            m_img->nChannels != img->nChannels || 
            m_img->depth != img->depth){

                cvReleaseImage(&m_img);
                m_img = (IplImage*)cvClone(img);
        }
        else
            memcpy(m_img->imageData, img->imageData, min(img->imageSize, m_img->imageSize));
        //cvCopy(img, m_img);
    }
}

inline void CvImgCtrl::setImage(const IplImage* img){
    _onlySetImage(img);
    onUpateImage();
}

inline void CvImgCtrl::OnDestroy(){
    CWnd::OnDestroy();
    if (m_img != 0)
        cvReleaseImage(&m_img);

    if (m_imgResize != 0)
        cvReleaseImage(&m_imgResize);
}

inline BOOL CvImgCtrl::OnEraseBkgnd(CDC* pDC){
    return TRUE;
}

inline void CvImgCtrl::onUpdateDisplayImage(){
    Invalidate();
    UpdateWindow();
}

inline void CvImgCtrl::OnPaint(){
    if(m_imgResize != 0){
        PAINTSTRUCT ps;
        HDC hDC = ::BeginPaint(m_hWnd, &ps);
        CRect rcPaint = ps.rcPaint;
        StretchDIBits(hDC, 0, 0, m_imgResize->width, m_imgResize->height, 0, 0, m_imgResize->width, m_imgResize->height, m_imgResize->imageData, &m_bmpHeader, DIB_RGB_COLORS, SRCCOPY);
        ::EndPaint(m_hWnd, &ps);
    }
    else
        CWnd::OnPaint();
}

inline void CvImgCtrl::OnNcDestroy(){
    CWnd::OnNcDestroy();

    if (m_autoDelete)
        delete this;
}

inline void CvImgCtrl::OnMouseMove(UINT nFlags, CPoint point){
    notifyParent(MsgMove, (LPARAM)&point);
}

inline void CvImgCtrl::OnLButtonDown(UINT nFlags, CPoint point){
    m_lastdownTime = ::GetTickCount();
    notifyParent(MsgLBDown, (LPARAM)&point);
}

inline void CvImgCtrl::OnLButtonUp(UINT nFlags, CPoint point){
    notifyParent(MsgLBUp, (LPARAM)&point);

    if(GetTickCount() - m_lastdownTime <= 300)
        notifyParent(MsgClick, (LPARAM)&point);
}

inline void CvImgCtrl::OnRButtonDown(UINT nFlags, CPoint point){
    notifyParent(MsgRBDown, (LPARAM)&point);
}

inline LRESULT CvImgCtrl::OnNcHitTest(CPoint point){
    return HTCLIENT;
}

inline void CvImgCtrl::OnMButtonDown(UINT nFlags, CPoint point){
    notifyParent(MsgMBDown, (LPARAM)&point);
}

inline void CvImgCtrl::OnMButtonUp(UINT nFlags, CPoint point){
    notifyParent(MsgMBUp, (LPARAM)&point);
}

inline void CvImgCtrl::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags){
    notifyParent(MsgKeyDown, nChar);
}

inline void CvImgCtrl::OnDropFiles(HDROP hDropInfo){
    CWnd::OnDropFiles(hDropInfo);
    notifyParent(MsgDragFile, (LPARAM)hDropInfo);
}