MFC上显示摄像头JPEG图片数据的两种方法

　　其一是借助opencv，其二是利用流对象。

方法一：

CvMat *mat;                                        //创建矩阵
mat = cvCreateMat(,,CV_8UC1);                //指定分配内存大小
cvInitMatHeader(mat,,,CV_8UC1,JPEGBuf);   　　
/*初始化矩阵信息头，这里的JPEGBuf就是JPEG图像数据的地址。现在很多摄像头是支持JPEG输出的，而且JPEG图像输出节                                                    省宽带。640*480大小的图片大小仅在20K以内。网上提到的什么视频采集卡，提供的SDK也基本提供JPEG数据，它获得的数                                                    据就是图像数据，而不是图像文件。*/
IplImage *pIplImage = cvDecodeImage(mat,CV_LOAD_IMAGE_COLOR);  //这里将JPEG图像数组转化为IplImage类，这里自动包含了解压JPEG格式图片功能。
if(pIplImage != NULL)   //如果解压失败得到的是NULL
{
　　CvvImage cimg;      //CvvImage类在opencv 2.2以后没有CvvImage类了，网上搜索这个类，有低版本的源代码，直接添加到工程里就可以用了。
　　cimg.CopyOf( pIplImage);   //复制图像
　　cimg.DrawToHDC(pMainDlg->m_DispHDC, &pMainDlg->m_DispRECT);  //显示图像
　　cvReleaseImage(&pIplImage);//释放图像
}
cvReleaseMat(&mat);  //释放矩阵

　  下面这个是个学习资料。　　

　　利用opencv读取图片并在MFC上显示，链接地址:http://licong1018.blog.163.com/blog/static/9026978420129239178934/

更新：因为自己需要，想要弄这个还要去翻看原来的工程文件。索性把CvvImage类贴在这里：

一、CvvImage.h

 #pragma once

 #ifndef CVVIMAGE_CLASS_DEF
 #define CVVIMAGE_CLASS_DEF

 #include "opencv.hpp"

 /* CvvImage class definition */
 class  CvvImage
 {
 public:
    CvvImage();
    virtual ~CvvImage();

    /* Create image (BGR or grayscale) */
    virtual bool  Create( int width, int height, int bits_per_pixel, int image_origin =  );

    /* Load image from specified file */
    virtual bool  Load( const char* filename, int desired_color =  );

    /* Load rectangle from the file */
    virtual bool  LoadRect( const char* filename,
       int desired_color, CvRect r );

 #if defined WIN32 || defined _WIN32
    virtual bool  LoadRect( const char* filename,
       int desired_color, RECT r )
    {
       return LoadRect( filename, desired_color,
          cvRect( r.left, r.top, r.right - r.left, r.bottom - r.top ));
    }
 #endif

    /* Save entire image to specified file. */
    virtual bool  Save( const char* filename );

    /* Get copy of input image ROI */
    virtual void  CopyOf( CvvImage& image, int desired_color = - );
    virtual void  CopyOf( IplImage* img, int desired_color = - );

    IplImage* GetImage() { return m_img; };
    virtual void  Destroy(void);

    /* width and height of ROI */
    int Width() { return !m_img ?  : !m_img->roi ? m_img->width : m_img->roi->width; };
    int Height() { return !m_img ?  : !m_img->roi ? m_img->height : m_img->roi->height;};
    int Bpp() { return m_img ? (m_img->depth & )*m_img->nChannels : ; };

    virtual void  Fill( int color );

    /* draw to highgui window */
    virtual void  Show( const char* window );

 #if defined WIN32 || defined _WIN32
    /* draw part of image to the specified DC */
    virtual void  Show( HDC dc, int x, int y, int width, int height,
       int from_x = , int from_y =  );
    /* draw the current image ROI to the specified rectangle of the destination DC */
    virtual void  DrawToHDC( HDC hDCDst, RECT* pDstRect );
 #endif

 protected:

    IplImage*  m_img;
 };

 typedef CvvImage CImage;

 #endif

二、CvvImage.cpp

 #include "StdAfx.h"
 #include "CvvImage.h"

 //////////////////////////////////////////////////////////////////////
 // Construction/Destruction
 //////////////////////////////////////////////////////////////////////

 CV_INLINE RECT NormalizeRect( RECT r );
 CV_INLINE RECT NormalizeRect( RECT r )
 {
    int t;

    if( r.left > r.right )
    {
       t = r.left;
       r.left = r.right;
       r.right = t;
    }

    if( r.top > r.bottom )
    {
       t = r.top;
       r.top = r.bottom;
       r.bottom = t;
    }

    return r;
 }

 CV_INLINE CvRect RectToCvRect( RECT sr );
 CV_INLINE CvRect RectToCvRect( RECT sr )
 {
    sr = NormalizeRect( sr );
    return cvRect( sr.left, sr.top, sr.right - sr.left, sr.bottom - sr.top );
 }

 CV_INLINE RECT CvRectToRect( CvRect sr );
 CV_INLINE RECT CvRectToRect( CvRect sr )
 {
    RECT dr;
    dr.left = sr.x;
    dr.top = sr.y;
    dr.right = sr.x + sr.width;
    dr.bottom = sr.y + sr.height;

    return dr;
 }

 CV_INLINE IplROI RectToROI( RECT r );
 CV_INLINE IplROI RectToROI( RECT r )
 {
    IplROI roi;
    r = NormalizeRect( r );
    roi.xOffset = r.left;
    roi.yOffset = r.top;
    roi.width = r.right - r.left;
    roi.height = r.bottom - r.top;
    roi.coi = ;

    return roi;
 }

 void  FillBitmapInfo( BITMAPINFO* bmi, int width, int height, int bpp, int origin )
 {
    assert( bmi && width >=  && height >=  && (bpp ==  || bpp ==  || bpp == ));

    BITMAPINFOHEADER* bmih = &(bmi->bmiHeader);

    memset( bmih, , sizeof(*bmih));
    bmih->biSize = sizeof(BITMAPINFOHEADER);
    bmih->biWidth = width;
    bmih->biHeight = origin ? abs(height) : -abs(height);
    bmih->biPlanes = ;
    bmih->biBitCount = (unsigned short)bpp;
    bmih->biCompression = BI_RGB;

    if( bpp ==  )
    {
       RGBQUAD* palette = bmi->bmiColors;
       int i;
       for( i = ; i < ; i++ )
       {
          palette[i].rgbBlue = palette[i].rgbGreen = palette[i].rgbRed = (BYTE)i;
          palette[i].rgbReserved = ;
       }
    }
 }

 CvvImage::CvvImage()
 {
    m_img = ;
 }

 void CvvImage::Destroy()
 {
    cvReleaseImage( &m_img );
 }

 CvvImage::~CvvImage()
 {
    Destroy();
 }

 bool  CvvImage::Create( int w, int h, int bpp, int origin )
 {
    const unsigned max_img_size = ;

    if( (bpp !=  && bpp !=  && bpp != ) ||
       (unsigned)w >=  max_img_size || (unsigned)h >= max_img_size ||
       (origin != IPL_ORIGIN_TL && origin != IPL_ORIGIN_BL))
    {
       assert(); // most probably, it is a programming error
       return false;
    }

    if( !m_img || Bpp() != bpp || m_img->width != w || m_img->height != h )
    {
       if( m_img && m_img->nSize == sizeof(IplImage))
          Destroy();

       /* prepare IPL header */
       m_img = cvCreateImage( cvSize( w, h ), IPL_DEPTH_8U, bpp/ );
    }

    if( m_img )
       m_img->origin = origin ==  ? IPL_ORIGIN_TL : IPL_ORIGIN_BL;

    return m_img != ;
 }

 void  CvvImage::CopyOf( CvvImage& image, int desired_color )
 {
    IplImage* img = image.GetImage();
    if( img )
    {
       CopyOf( img, desired_color );
    }
 }

 #define HG_IS_IMAGE(img)                                                  \
    ((img) !=  && ((const IplImage*)(img))->nSize == sizeof(IplImage) && \
    ((IplImage*)img)->imageData != )

 void  CvvImage::CopyOf( IplImage* img, int desired_color )
 {
    if( HG_IS_IMAGE(img) )
    {
       int color = desired_color;
       CvSize size = cvGetSize( img ); 

       if( color <  )
          color = img->nChannels > ;

       if( Create( size.width, size.height,
          (!color ?  : img->nChannels >  ? img->nChannels : )*,
          img->origin ))
       {
          cvConvertImage( img, m_img,  );
       }
    }
 }

 bool  CvvImage::Load( const char* filename, int desired_color )
 {
    IplImage* img = cvLoadImage( filename, desired_color );
    if( !img )
       return false;

    CopyOf( img, desired_color );
    cvReleaseImage( &img );

    return true;
 }

 bool  CvvImage::LoadRect( const char* filename,
                    int desired_color, CvRect r )
 {
    if( r.width <  || r.height <  ) return false;

    IplImage* img = cvLoadImage( filename, desired_color );
    if( !img )
       return false;

    if( r.width ==  || r.height ==  )
    {
       r.width = img->width;
       r.height = img->height;
       r.x = r.y = ;
    }

    if( r.x > img->width || r.y > img->height ||
       r.x + r.width <  || r.y + r.height <  )
    {
       cvReleaseImage( &img );
       return false;
    }

    /* truncate r to source image */
    if( r.x <  )
    {
       r.width += r.x;
       r.x = ;
    }
    if( r.y <  )
    {
       r.height += r.y;
       r.y = ;
    }

    if( r.x + r.width > img->width )
       r.width = img->width - r.x;

    if( r.y + r.height > img->height )
       r.height = img->height - r.y;

    cvSetImageROI( img, r );
    CopyOf( img, desired_color );

    cvReleaseImage( &img );
    return true;
 }

 bool  CvvImage::Save( const char* filename )
 {
    if( !m_img )
       return false;
    cvSaveImage( filename, m_img );
    return true;
 }

 void  CvvImage::Show( const char* window )
 {
    if( m_img )
       cvShowImage( window, m_img );
 }

 void  CvvImage::Show( HDC dc, int x, int y, int w, int h, int from_x, int from_y )
 {
    if( m_img && m_img->depth == IPL_DEPTH_8U )
    {
       uchar buffer[sizeof(BITMAPINFOHEADER) + ];
       BITMAPINFO* bmi = (BITMAPINFO*)buffer;
       int bmp_w = m_img->width, bmp_h = m_img->height;

       FillBitmapInfo( bmi, bmp_w, bmp_h, Bpp(), m_img->origin );

       from_x = MIN( MAX( from_x,  ), bmp_w -  );
       from_y = MIN( MAX( from_y,  ), bmp_h -  );

       int sw = MAX( MIN( bmp_w - from_x, w ),  );
       int sh = MAX( MIN( bmp_h - from_y, h ),  );

       SetDIBitsToDevice(
          dc, x, y, sw, sh, from_x, from_y, from_y, sh,
          m_img->imageData + from_y*m_img->widthStep,
          bmi, DIB_RGB_COLORS );
    }
 }

 void  CvvImage::DrawToHDC( HDC hDCDst, RECT* pDstRect )
 {
    if( pDstRect && m_img && m_img->depth == IPL_DEPTH_8U && m_img->imageData )
    {
       uchar buffer[sizeof(BITMAPINFOHEADER) + ];
       BITMAPINFO* bmi = (BITMAPINFO*)buffer;
       int bmp_w = m_img->width, bmp_h = m_img->height;

       CvRect roi = cvGetImageROI( m_img );
       CvRect dst = RectToCvRect( *pDstRect );

       if( roi.width == dst.width && roi.height == dst.height )
       {
          Show( hDCDst, dst.x, dst.y, dst.width, dst.height, roi.x, roi.y );
          return;
       }

       if( roi.width > dst.width )
       {
          SetStretchBltMode(
             hDCDst,           // handle to device context
             HALFTONE );
       }
       else
       {
          SetStretchBltMode(
             hDCDst,           // handle to device context
             COLORONCOLOR );
       }

       FillBitmapInfo( bmi, bmp_w, bmp_h, Bpp(), m_img->origin );

       ::StretchDIBits(
          hDCDst,
          dst.x, dst.y, dst.width, dst.height,
          roi.x, roi.y, roi.width, roi.height,
          m_img->imageData, bmi, DIB_RGB_COLORS, SRCCOPY );
    }
 }

 void  CvvImage::Fill( int color )
 {
    cvSet( m_img, cvScalar(color&,(color>>)&,(color>>)&,(color>>)&) );
 }

方法二：

void CTestDlg::DisplayJPEG(HDC hDC,unsigned char *buf,UINT bufLen,int rectWidth,int rectHeight)
{
    HGLOBAL hImageMemory=GlobalAlloc(GMEM_MOVEABLE, bufLen);//给图片分配全局内存
    void *pImageMemory=GlobalLock(hImageMemory);            //锁定内存
    if(pImageMemory == NULL)
    {
        TRACE("can't Get Global Memory!\n");
        goto ret;
    }
    memcpy(pImageMemory,buf,bufLen);                        //读取图片到全局内存当中
    GlobalUnlock(hImageMemory);                             //解锁内存

    IStream *pIStream;                                        //创建一个IStream接口指针，用来保存图片流
    IPicture *pIPicture;                                      //创建一个IPicture接口指针，表示图片对象
    CreateStreamOnHGlobal(hImageMemory, false,&pIStream);     //用全局内存初使化IStream接口指针
    OleLoadPicture(pIStream, , false, IID_IPicture,(LPVOID*)&(pIPicture));//用OleLoadPicture获得IPicture接口指针
    if(pIStream == NULL)
    {
        TRACE("can't Get pIStream!\n");
        goto ret;
    }

    OLE_XSIZE_HIMETRIC hmWidth;
    OLE_YSIZE_HIMETRIC hmHeight;

    if(pIPicture == NULL)
    {
        TRACE("can't Get Picture Info!\n");
        goto ret;
    }

    pIPicture->get_Width(&hmWidth);  //用接口方法获得图片的宽和高
    pIPicture->get_Height(&hmHeight);
    pIPicture->Render(hDC,,,rectWidth,rectHeight,,hmHeight,hmWidth,-hmHeight,NULL);//在指定的DC上绘出图片

    //以下代码为了保存一张图片
    ///////////////////////////////////////////////////////////////////////////////////
    if(m_bSavePic == TRUE)
    {
        m_SaveFile.Open("Hello.jpg",CFile::modeCreate|CFile::modeWrite);           //读写方式打开
        m_SaveFile.Seek(,CFile::begin);
        m_SaveFile.Write(buf,bufLen);                                             //将文件读入缓存
        m_SaveFile.Close();
        m_bSavePic = FALSE;
    }
    ///////////////////////////////////////////////////////////////////////////////////

    pIStream->Release(); //释放pIStream
    pIPicture->Release(); //释放pIPicture
ret:
    GlobalFree(hImageMemory); //释放全局内存
}