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(640,480,CV_8UC1);                //指定分配内存大小
cvInitMatHeader(mat,640,480,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 = 0 );

   /* Load image from specified file */
   virtual bool  Load( const char* filename, int desired_color = 1 );

   /* 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 = -1 );
   virtual void  CopyOf( IplImage* img, int desired_color = -1 );

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

   /* width and height of ROI */
   int Width() { return !m_img ? 0 : !m_img->roi ? m_img->width : m_img->roi->width; };
   int Height() { return !m_img ? 0 : !m_img->roi ? m_img->height : m_img->roi->height;};
   int Bpp() { return m_img ? (m_img->depth & 255)*m_img->nChannels : 0; };

   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 = 0, int from_y = 0 );
   /* 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 = 0;

   return roi;
}

void  FillBitmapInfo( BITMAPINFO* bmi, int width, int height, int bpp, int origin )
{
   assert( bmi && width >= 0 && height >= 0 && (bpp == 8 || bpp == 24 || bpp == 32));

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

   memset( bmih, 0, sizeof(*bmih));
   bmih->biSize = sizeof(BITMAPINFOHEADER);
   bmih->biWidth = width;
   bmih->biHeight = origin ? abs(height) : -abs(height);
   bmih->biPlanes = 1;
   bmih->biBitCount = (unsigned short)bpp;
   bmih->biCompression = BI_RGB;

   if( bpp == 8 )
   {
      RGBQUAD* palette = bmi->bmiColors;
      int i;
      for( i = 0; i < 256; i++ )
      {
         palette[i].rgbBlue = palette[i].rgbGreen = palette[i].rgbRed = (BYTE)i;
         palette[i].rgbReserved = 0;
      }
   }
}

CvvImage::CvvImage()
{
   m_img = 0;
}

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 = 10000;

   if( (bpp != 8 && bpp != 24 && bpp != 32) ||
      (unsigned)w >=  max_img_size || (unsigned)h >= max_img_size ||
      (origin != IPL_ORIGIN_TL && origin != IPL_ORIGIN_BL))
   {
      assert(0); // 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/8 );
   }

   if( m_img )
      m_img->origin = origin == 0 ? IPL_ORIGIN_TL : IPL_ORIGIN_BL;

   return m_img != 0;
}

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


#define HG_IS_IMAGE(img)                                                  
   ((img) != 0 && ((const IplImage*)(img))->nSize == sizeof(IplImage) && 
   ((IplImage*)img)->imageData != 0)


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

      if( color < 0 )
         color = img->nChannels > 1;

      if( Create( size.width, size.height,
         (!color ? 1 : img->nChannels > 1 ? img->nChannels : 3)*8,
         img->origin ))
      {
         cvConvertImage( img, m_img, 0 );
      }
   }
}


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 < 0 || r.height < 0 ) return false;

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

   if( r.width == 0 || r.height == 0 )
   {
      r.width = img->width;
      r.height = img->height;
      r.x = r.y = 0;
   }

   if( r.x > img->width || r.y > img->height ||
      r.x + r.width < 0 || r.y + r.height < 0 )
   {
      cvReleaseImage( &img );
      return false;
   }

   /* truncate r to source image */
   if( r.x < 0 )
   {
      r.width += r.x;
      r.x = 0;
   }
   if( r.y < 0 )
   {
      r.height += r.y;
      r.y = 0;
   }

   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) + 1024];
      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, 0 ), bmp_w - 1 );
      from_y = MIN( MAX( from_y, 0 ), bmp_h - 1 );

      int sw = MAX( MIN( bmp_w - from_x, w ), 0 );
      int sh = MAX( MIN( bmp_h - from_y, h ), 0 );

      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) + 1024];
      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&255,(color>>8)&255,(color>>16)&255,(color>>24)&255) );
}

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!
");
        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, 0, false, IID_IPicture,(LPVOID*)&(pIPicture));//用OleLoadPicture获得IPicture接口指针
    if(pIStream == NULL)
    {
        TRACE("can't Get pIStream!
");
        goto ret;
    }

    OLE_XSIZE_HIMETRIC hmWidth;
    OLE_YSIZE_HIMETRIC hmHeight;

    if(pIPicture == NULL)
    {
        TRACE("can't Get Picture Info!
");
        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,0,0,rectWidth,rectHeight,0,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(0,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
}