位图透明色的裁剪

	COLORREF crl;

	GetWindowRect(&m_rtWnd);

	CRgn wndRgn, rgnTemp;



	CDC* pDC = GetWindowDC();

	CDC dcCompatible;



	dcCompatible.CreateCompatibleDC(pDC);

	CBitmap* pOldBitmap = dcCompatible.SelectObject(&m_bitmap);

	

	wndRgn.CreateRectRgn(0,0,m_rtWnd.Width(),m_rtWnd.Height());

	for(int x=0; x<m_rtWnd.Width(); x++)

	{

		for(int y=0; y<m_rtWnd.Height(); y++)

		{

			crl = dcCompatible.GetPixel(x, y);

			if(crl == TRANSCOLOR)

			{

				rgnTemp.CreateRectRgn(x, y, x+1, y+1);				

				wndRgn.CombineRgn(&wndRgn,&rgnTemp, RGN_XOR);//裁减掉透明色区域

				rgnTemp.DeleteObject();

			}

		}

	}



	//设置最终的窗口范围

	SetWindowRgn((HRGN)wndRgn,TRUE);

	

	dcCompatible.SelectObject(pOldBitmap);



	ReleaseDC(pDC);

	ReleaseDC(&dcCompatible);