DirectShow 加载logo水印

typedef struct _VMRALPHABITMAP {   

 DWORD dwFlags;                                                                                                          //指明从哪儿获取位图

HDC hdc;                                                                                                                         //指定的设备上下文DC。如果指定为NULL，则位图是从一个DirectDraw surface上获取。

LPDIRECTDRAWSURFACE7 pDDS;                                                                            // 指向 DirectDraw surface的一个指针。如果指定为NULL则,位图是从GDI DC中获取。

RECT rSrc;                                                                                                                     //指明源矩形

NORMALIZEDRECT rDest;                                                                                            //指定目标矩形

 FLOAT fAlpha;                                                                                                               //指定alpha混合值，必须有一个在0.0到1.0之间的值（含） 。

COLORREF clrSrcKey;                                                                                                  //指定需要取消图片的背景颜色

} VMRALPHABITMAP;typedef struct _VMRALPHABITMAP *PVMRALPHABITMAP;

 

dwFlags应为以下值

 

VMRBITMAP_DISABLE (0x00000001)	现在不需要位图
VMRBITMAP_HDC (0x00000002)	从HDC中获取位图
VMRBITMAP_ENTIREDDS (0x00000004)	从整个DirectDraw surface获取位图.当这个被指定时, 指定rSrc没有用.
VMRBITMAP_SRCCOLORKEY (0x00000008)	clrSrcKey 值可用，当在混合运算渲染位图时，这个值将被用到
VMRBITMAP_SRCRECT (0x00000010)

 

HRESULT CVMRPlayMovive::BlendApplicationImage(HWND hwndApp)
{
	LONG cx, cy;
	HRESULT hr;
	RECT rc={0};
	hr = pWC->GetNativeVideoSize(&cx, &cy, NULL, NULL);
	if (FAILED(hr))
		return hr;

	HINSTANCE hInstance = (HINSTANCE)GetWindowLong(m_hwnd,GWL_HINSTANCE); 
	HBITMAP hbm = LoadBitmap(hInstance, MAKEINTRESOURCE(IDB_BITMAP3));
    //加载位图
	BITMAP bm;
	HBITMAP hbmOld;
	HDC hdc = GetDC(hwndApp);
	HDC hdcBmp = CreateCompatibleDC(hdc);
	ReleaseDC(hwndApp, hdc);
	GetObject(hbm, sizeof(bm), &bm);
	hbmOld = (HBITMAP)SelectObject(hdcBmp, hbm);

	VMRALPHABITMAP bmpInfo;
	ZeroMemory(&bmpInfo, sizeof(bmpInfo) );
	bmpInfo.dwFlags = VMRBITMAP_HDC;
	bmpInfo.hdc = hdcBmp;


	g_nBitmapWidth = bm.bmWidth;
	g_nImageWidth  = bm.bmWidth / NUM_IMAGES_IN_BITMAP;
	SetRect(&rc,0,0,g_nBitmapWidth, bm.bmHeight);
	bmpInfo.rSrc = rc;

	// rDest specifies the destination rectangle in composition space (0.0f to 1.0f)
	bmpInfo.rDest.left   = (float)(cx - g_nImageWidth) / (float)cx - EDGE_BUFFER;
	bmpInfo.rDest.top    = (float)(cy - bm.bmHeight)   / (float)cy - EDGE_BUFFER;
	bmpInfo.rDest.right  = 1.0f - EDGE_BUFFER;
	bmpInfo.rDest.bottom = 1.0f - EDGE_BUFFER;

	g_rDest = bmpInfo.rDest;
	g_rSrc  = bmpInfo.rSrc;

	g_fBitmapCompWidth = (float)g_nImageWidth / (float)cx;
	bmpInfo.fAlpha = 0.0;

	SetColorRef(bmpInfo);

	hr = pBMP->SetAlphaBitmap(&bmpInfo);
	if (FAILED(hr))
		Msg(TEXT("SetAlphaBitmap FAILED!  Bitmap operations will fail. hr=0x%x\r\n"), hr);

	// Clean up GDI resources
	DeleteObject(SelectObject(hdcBmp, hbmOld));
	DeleteObject(hbm);
	DeleteDC(hdcBmp);

	// If setting the alpha bitmap succeeded, update its parameters
	if (SUCCEEDED(hr))
	{
		SetRect(&rc, 0, 0, g_nImageWidth, bm.bmHeight);
		bmpInfo.rSrc = rc;
		g_rSrcSingle = rc;
		bmpInfo.dwFlags = VMRBITMAP_SRCRECT | VMRBITMAP_SRCCOLORKEY;
		bmpInfo.fAlpha = TRANSPARENCY_VALUE;
		hr = pBMP->UpdateAlphaBitmapParameters(&bmpInfo);
		if (FAILED(hr))
			Msg(TEXT("UpdateAlphaBitmapParameters FAILED!  hr=0x%x\r\n"), hr);
	}

	return hr;
}

void CVMRPlayMovive::SetColorRef(VMRALPHABITMAP& bmpInfo)
{
	bmpInfo.clrSrcKey = RGB(255, 0, 0);       
	bmpInfo.dwFlags |= VMRBITMAP_SRCCOLORKEY;
}