Gdi+ 加载Gif图片(BYTE*转为IStream)

时间 2019-11-10 标签 gdi 加载 gif 图片 byte 转为 istream

今天工做中遇到GDI+加载图片流的问题，网上找了不少资料都不行，绘制其余帧老是模糊，，ui

网上的方法代码以下：blog

注：pImageData是BYTE*类型 ,dImageLen是DWORD类型;

HGLOBAL m_hMem = GlobalAlloc(GMEM_FIXED, dImageLen);   
BYTE* pmem = (BYTE*)GlobalLock(m_hMem);   
memcpy(pmem,pImageData,dImageLen);   
IStream* pstm;   
HRESULT ht =  CreateStreamOnHGlobal(m_hMem,FALSE,&pstm);   
if (ht != S_OK)  
{  
	GlobalFree(m_hMem);  
	return ;  
}  
m_pImage=Gdiplus::Image::FromStream(pstm);
GlobalUnlock(m_hMem);   

pstm->Release();   	
GlobalFree(m_hMem); 

if (m_pImage)
{
	UINT count = m_pImage->GetFrameDimensionsCount();
	if (count > 0 && m_pImage->GetLastStatus() == 0)
	{
		m_pDimensionIDs = new GUID[count]; 
		m_pImage->GetFrameDimensionsList(m_pDimensionIDs, count); 
		WCHAR strGuid[39]; 
		StringFromGUID2(m_pDimensionIDs[0], strGuid, 39); 
		m_FrameCount = m_pImage->GetFrameCount(&m_pDimensionIDs[0]);
		UINT TotalBuffer = m_pImage->GetPropertyItemSize(PropertyTagFrameDelay); 
		m_pItem = (Gdiplus::PropertyItem*)malloc(TotalBuffer); 
		m_pImage->GetPropertyItem(PropertyTagFrameDelay, TotalBuffer, m_pItem); 
		m_bStatOK = TRUE;
	}
}

　老是绘制出现问题后本身找了方法解决问题，代码以下：图片

注：m_pstream是类成员，在类析构的时候释放 ，，，pImageData是BYTE*类型 ,dImageLen是DWORD类型;
	
if(CreateStreamOnHGlobal(NULL, TRUE, &m_pStream) == S_OK)
	{
		ULONG ulWritten = 0;
		m_pStream->Write(pImageData, dImageLen, &ulWritten);

		//Rewind the argument stream;
		LARGE_INTEGER lInt;
		lInt.QuadPart = 0;
		m_pStream->Seek(lInt, STREAM_SEEK_SET, NULL);

		//Read the lenght of the argument stream;
		STATSTG statSTG;
		long dwResult = m_pStream->Stat(&statSTG, STATFLAG_DEFAULT);
		if(dwResult != S_OK)
		{			
			return ;
		}
		m_pImage=Gdiplus::Image::FromStream(m_pStream);
		if (m_pImage)
		{
			UINT count = m_pImage->GetFrameDimensionsCount();
			if (count > 0 && m_pImage->GetLastStatus() == 0)
			{
				m_pDimensionIDs = new GUID[count]; 
				m_pImage->GetFrameDimensionsList(m_pDimensionIDs, count); 
				WCHAR strGuid[39]; 
				StringFromGUID2(m_pDimensionIDs[0], strGuid, 39); 
				m_FrameCount = m_pImage->GetFrameCount(&m_pDimensionIDs[0]);
				UINT TotalBuffer = m_pImage->GetPropertyItemSize(PropertyTagFrameDelay); 
				m_pItem = (Gdiplus::PropertyItem*)malloc(TotalBuffer); 
				m_pImage->GetPropertyItem(PropertyTagFrameDelay, TotalBuffer, m_pItem); 
				m_bStatOK = TRUE;
			}
		}				
	}

这样经过定时器绘制其余帧就没有图片不成像问题ip

DrawGif(HDC hDC, const RECT& rc) 
{
	if (NULL == m_pItem)
		return 0;

    m_pImage->SelectActiveFrame(&Gdiplus::FrameDimensionTime, m_iCurrentFrame);

    unsigned msec = ((int*)m_pItem->value)[m_iCurrentFrame] * 10;

	Graphics g( hDC );
	g.SetSmoothingMode(Gdiplus::SmoothingModeHighQuality);
	g.DrawImage( m_pImage, rc.left, rc.top, rc.right-rc.left, rc.bottom - rc.top );

    return msec;
}