gdi+把bmp存为jpg

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

}

void BMP2JPG(CString strBMPFile,CString strJPGFile)

{

CLSID encoderClsid;

WCHAR strGuid[39];

if(GetEncoderClsid(L"image/jpeg", &encoderClsid) >= 0)

StringFromGUID2(encoderClsid, strGuid, 39);

Image image(strBMPFile.AllocSysString());

image.Save(strJPGFile.AllocSysString(),&encoderClsid,NULL);

}