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我正在尝试在位图中创建一个具有 RGB ( 0, 0, 255 ) 识别的透明区域的子窗口，该位图中将在整个子窗口中绘制。

以下是我用来使其透明的代码，问题是子窗口透明部分下方的父窗口也变得透明，并且通过它可以看到桌面。

hwndChild = ::CreateWindowEx ( 0, "mycustomwindow", txt.c_str (  ), WS_CLIPCHILDREN | WS_CLIPSIBLINGS | WS_CHILD, x, y, width, height, parent, 0, hInstance, ( LPVOID ) this ) ;

transparent (  );



void transparent (  )
{



    HMODULE hUser32 = GetModuleHandle (  ( "USER32.DLL" )  );



    COLORREF g_ColourKey    = 0xFF00FF;     // 0,0,255(magenta) in RGB hex value


    typedef BOOL ( WINAPI *lpfnSetLayeredWindowAttributes ) ( HWND hWnd, COLORREF crKey, BYTE bAlpha, DWORD dwFlags );
    lpfnSetLayeredWindowAttributes SetLayeredWindowAttributes;

    SetLayeredWindowAttributes = ( lpfnSetLayeredWindowAttributes ) GetProcAddress ( hUser32, "SetLayeredWindowAttributes" );

    if( SetLayeredWindowAttributes == NULL ) 
    {


        MessageBox ( hwndChild, "Error, cannot load window transparency\n REASON: Could not load User32.DLL", "Error!", MB_ICONSTOP | MB_OK );


    }
    else
    { 


        DWORD dwStyle = GetWindowLong ( hwndChild, GWL_STYLE ); 

        dwStyle &= ~( WS_CAPTION | WS_SIZEBOX ); 

        SetWindowLong  ( hwndChild, GWL_STYLE, dwStyle );


        InvalidateRect ( hwndChild, NULL, true ); 

        SetWindowPos   ( hwndChild, NULL, 0, 0, wWidth, wHeight, SWP_NOMOVE | SWP_NOZORDER );


        SetWindowLong  ( hwndChild, GWL_EXSTYLE, GetWindowLong ( hwndChild, GWL_EXSTYLE ) | WS_EX_LAYERED );

        SetLayeredWindowAttributes ( hwndChild, g_ColourKey, 0, LWA_COLORKEY );


    }



};

父窗口（它是顶层窗口）本身使用相同的函数来使某些部分透明，具有以下 dwStyle ： WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN

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