从内存中加载png<摘自MFC源码>

最新推荐文章于 2024-05-29 00:16:50 发布

原创最新推荐文章于 2024-05-29 00:16:50 发布 · 1.8k 阅读

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CC 4.0 BY-SA版权

本文介绍了一个名为CPngImage的类中的LoadFromBuffer成员函数实现细节。该函数负责从内存缓冲区加载PNG图像，并利用GDI+支持来完成加载过程。文中详细解释了如何分配内存、创建流、加载图像并进行资源管理。

BOOL CPngImage::LoadFromBuffer (LPBYTE lpBuffer, UINT uiSize)
{
	if (!afxGlobalData.bGDIPlusSupport)
	{
		return FALSE;
	}

	ASSERT(lpBuffer != NULL);

	HGLOBAL hRes = ::GlobalAlloc (GMEM_MOVEABLE, uiSize);
	if (hRes == NULL)
	{
		return FALSE;
	}

	IStream* pStream = NULL;
	LPVOID lpResBuffer = ::GlobalLock (hRes);
	ASSERT (lpResBuffer != NULL);

	memcpy (lpResBuffer, lpBuffer, uiSize);

	HRESULT hResult = ::CreateStreamOnHGlobal (hRes, TRUE, &pStream);

	if (hResult != S_OK)
	{
		return FALSE;
	}

	if (CMFCToolBarImages::m_bMultiThreaded)
	{
		CMFCToolBarImages::m_CriticalSection.Lock ();
	}

	if (m_pImage == NULL)
	{
		m_pImage = new CImage;
		ENSURE(m_pImage != NULL);
	}

	m_pImage->Load (pStream);
	pStream->Release ();

	BOOL bRes = Attach (m_pImage->Detach ());

	if (CMFCToolBarImages::m_bMultiThreaded)
	{
		CMFCToolBarImages::m_CriticalSection.Unlock ();
	}

	return bRes;
}