从资源中加载jpg, png到GDI+ Image

从资源中加载jpg和png文件， 貌似不应该是个大问题， 一google结果一大堆， 却有两个陷阱，trap啊

1， 是Bitmap(RT_BITMAP)类型的图片无法加载， RT_BITMAP是预定义类型， 资源里面没有bmp文件的头， SizeofResource
的返回值要比图片文件少几个字节，因为少了这几个字节， 所以GDI+会返回invalid parameter错误。

2， 从IStream里面创建出来的Image对象似乎会引用到堆里面的内存，
如果hBuffer被释放了， 创建的Image的内容就会被破坏，有时只能画出一小部分图片， 有时整个图片就是空白， 视当时的内存状况而定。调用Image的Clone也没用。

CYourClass::~CYourClass()
{
for(IMG_VECTOR::iterator it = m_arImage.begin(); it != m_arImage.end(); it++)
delete *it;
for(HGLB_VECTOR::iterator it = m_arGlobal.begin(); it != m_arGlobal.end(); it++)
{
::GlobalUnlock(*it);
::GlobalFree(*it);
}
}

void CYourClass::AddImage(HMODULE hInst, UINT nResourceID, LPCTSTR lpType)
{
if(lpType == RT_BITMAP)
{
//GDI+ can not load RT_BITMAP resouce,
//because they are predefined resource,
//they don't contains the image file header.
assert(FALSE);
return;
}

HRSRC hResource = ::FindResource(hInst, MAKEINTRESOURCE(nResourceID), lpType);
if (!hResource)
return;

DWORD imageSize = ::SizeofResource(hInst, hResource);
if (!imageSize)
return;

const void* pResourceData = ::LockResource(::LoadResource(hInst, hResource));
if (!pResourceData)
return;

HGLOBAL hBuffer = ::GlobalAlloc(GMEM_FIXED, imageSize);
if (NULL == hBuffer)
return;

void* pBuffer = ::GlobalLock(hBuffer);
if (pBuffer)
{
CopyMemory(pBuffer, pResourceData, imageSize);
IStream* pStream = NULL;
if (::CreateStreamOnHGlobal(hBuffer, FALSE, &pStream) == S_OK)
{
Gdiplus::Image * pImage = Gdiplus::Image::FromStream(pStream);
pStream->Release();
if (pImage)
{
if (pImage->GetLastStatus() == Gdiplus::Ok &&
pImage->GetWidth() > 0)
{
m_arImage.push_back(pImage);
//it seems the image will take usage of the global memory.
//so the global memory should be kept until the image destroy.
m_arGlobal.push_back(hBuffer);
return;
}

delete pImage;
}
}
::GlobalUnlock(hBuffer);
}
::GlobalFree(hBuffer);
}