MFC制作不规则窗体

ModifyStyleEx(0,WS_EX_LAYERED);
m_image.Load(_T("res\\test1.png"));
DrawUI();

void CdirectUITest2Dlg::DrawUI()
{
HDC hDC=::GetDC(m_hWnd);
HDC hMemDC=::CreateCompatibleDC(hDC);

BITMAPINFO bitmapinfo;
bitmapinfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bitmapinfo.bmiHeader.biBitCount = 32;
bitmapinfo.bmiHeader.biHeight =500;
bitmapinfo.bmiHeader.biWidth = 500;
bitmapinfo.bmiHeader.biPlanes = 1;
bitmapinfo.bmiHeader.biCompression=BI_RGB;
bitmapinfo.bmiHeader.biXPelsPerMeter=0;
bitmapinfo.bmiHeader.biYPelsPerMeter=0;
bitmapinfo.bmiHeader.biClrUsed=0;
bitmapinfo.bmiHeader.biClrImportant=0;
bitmapinfo.bmiHeader.biSizeImage = bitmapinfo.bmiHeader.biWidth * bitmapinfo.bmiHeader.biHeight * bitmapinfo.bmiHeader.biBitCount / 8;
HBITMAP hBitmap=::CreateDIBSection (hMemDC,&bitmapinfo, 0,NULL, 0, 0);
HBITMAP hOldBitmap = (HBITMAP)::SelectObject (hMemDC,hBitmap);

//画出各个界面元素----------------------
m_image.Draw( hMemDC,0,0 );

//设置透明窗口-------------------------------------------------
CPoint DestPt(0,0);
CSize psize(500,500);
BLENDFUNCTION blendFunc32bpp;
blendFunc32bpp.AlphaFormat = AC_SRC_ALPHA;
blendFunc32bpp.BlendFlags = 0;
blendFunc32bpp.BlendOp = AC_SRC_OVER;
blendFunc32bpp.SourceConstantAlpha = 255;
::UpdateLayeredWindow(m_hWnd,hDC,NULL,&psize,hMemDC,&DestPt,0,&blendFunc32bpp,ULW_ALPHA);

//释放资源-------------------------------------------------
::SelectObject (hMemDC,hOldBitmap);
::DeleteObject(hBitmap);
::DeleteDC(hMemDC);
::ReleaseDC(m_hWnd,hDC);
}

void CdirectUITest2Dlg::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
ReleaseCapture ();
SendMessage (WM_NCLBUTTONDOWN, HTCAPTION, 0);
CDialogEx::OnLButtonDown(nFlags, point);
}