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
}