VC 实现BMP转换到JPG、JPG转换到BMP

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)   {       UINT num = 0;                     // number of image encoders       UINT size = 0;                   // size of the image encoder array in bytes       ImageCodecInfo* pImageCodecInfo = NULL;       GetImageEncodersSize(&num, &size);       if(size == 0)           return -1;     //   Failure           pImageCodecInfo = (ImageCodecInfo*)(malloc(size));       if(pImageCodecInfo == NULL)           return -1;     //   Failure           GetImageEncoders(num, size, pImageCodecInfo);       for(UINT j = 0; j < num; ++j)       {           if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )           {               *pClsid = pImageCodecInfo[j].Clsid;               free(pImageCodecInfo);               return j;     //   Success           }               }       free(pImageCodecInfo);       return -1;     //   Failure   }/****************BMP转JPG*********用法示例**************************Bitmap newbitmap(L"d:\\d.bmp");//加载BMPconst unsigned short *pFileName=L"d:\\new.jpg";//保存路径SaveFile(&newbitmap,pFileName );************************************************************/void SaveFile(Bitmap* pImage, const wchar_t* pFileName)//{    EncoderParameters encoderParameters;    CLSID jpgClsid; GetEncoderClsid(L"image/jpeg", &jpgClsid);    encoderParameters.Count = 1;    encoderParameters.Parameter[0].Guid = EncoderQuality;    encoderParameters.Parameter[0].Type = EncoderParameterValueTypeLong;    encoderParameters.Parameter[0].NumberOfValues = 1;    // Save the image as a JPEG with quality level 100.    ULONG             quality;    quality = 100;    encoderParameters.Parameter[0].Value = &quality;    Status status = pImage->Save(pFileName, &jpgClsid, &encoderParameters);    if (status != Ok)     {        wprintf(L"%d Attempt to save %s failed.\n", status, pFileName);    }}// 将当前屏幕保存成为jpg图片       // 参数   xs = 图象x岽笮?   ys = 图象y轴大小,   quality = jpeg图象质量       void SaveCurScreenJpg(LPCWSTR   pszFileName,   int   xs,   int   ys,   int   quality)   {       HWND hwnd = ::GetDesktopWindow();       HDC hdc = GetWindowDC(NULL);       int x = GetDeviceCaps(hdc, HORZRES);       int y = GetDeviceCaps(hdc, VERTRES);       HBITMAP hbmp = ::CreateCompatibleBitmap(hdc, x, y), hold;       HDC hmemdc = ::CreateCompatibleDC(hdc);       hold = (HBITMAP)::SelectObject(hmemdc,   hbmp);       BitBlt(hmemdc, 0, 0, x, y, hdc, 0, 0, SRCCOPY);       SelectObject(hmemdc, hold);           Bitmap bit(xs, ys), bit2(hbmp, NULL);       Graphics g(&bit);       g.ScaleTransform((float)xs/x,   (float)ys/y);       g.DrawImage(&bit2,   0,   0);           CLSID                           encoderClsid;       EncoderParameters   encoderParameters;           encoderParameters.Count   =   1;       encoderParameters.Parameter[0].Guid   =   EncoderQuality;       encoderParameters.Parameter[0].Type   =   EncoderParameterValueTypeLong;       encoderParameters.Parameter[0].NumberOfValues   =   1;       encoderParameters.Parameter[0].Value   =   &quality;           GetEncoderClsid(L"image/jpeg",   &encoderClsid);       bit.Save(pszFileName,   &encoderClsid,   &encoderParameters);          ::DeleteObject(hbmp);       ::DeleteObject(hmemdc);       return;   }  HBITMAP   ReturnHBITMAP(CString   FileName)//FileName可能是bmp、dib、png、gif、jpeg/jpg、tiff、emf等文件的文件名 {           Bitmap   tempBmp(FileName.AllocSysString())   ;         Color       backColor;               HBITMAP       HBitmap;           tempBmp.GetHBITMAP(backColor,&HBitmap);         return   HBitmap;}