Win32 (GDI) - Set Opacity of STATIC Control

问题

I'm using C - (NO MFC or GDI+) :-)

What I want is to set the opacity of my child window to let say 100 (my child window is a STATIC control). I was wondering if this is even possible and if so can someone please point me to the right direction on how to do it.

Here is my setup:

I create my Parent window as follow:

HWND     hWnd;
WNDCLASS wndCls_s;


wndCls_s.style         = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
wndCls_s.lpfnWndProc   = MainWndProc;
wndCls_s.cbClsExtra    = 0;
wndCls_s.cbWndExtra    = 0;
wndCls_s.hInstance     = hInstance;
wndCls_s.hIcon         = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_BSN_64));
wndCls_s.hCursor       = LoadCursor(NULL, IDC_ARROW);
wndCls_s.hbrBackground = CreateSolidBrush(RGB(0, 0, 0));
wndCls_s.lpszMenuName  = NULL;
wndCls_s.lpszClassName = pszCName;

if (RegisterClass(&wndCls_s) == 0)
    return EXIT_FAILURE;


/* Creating Window */
hWnd = CreateWindow(
    pszCName, pszCName,
    WS_VISIBLE | WS_POPUP | WS_SYSMENU | WS_CLIPCHILDREN,
    0, 0, WND_WIDTH, WND_HEIGHT,
    NULL, NULL, hInstance, NULL);

In my MainWndProc:

case WM_CREATE: 
    {   
    HWND hWndChild = CreateWindow(
        L"STATIC", (LPCTSTR) NULL,
        WS_CHILD | WS_VISIBLE,
        10, 10, 110, 110,
        hWnd, (HMENU) (int) 10000, 
        g_hInst, NULL);
    }
    break;
case WM_CTLCOLORSTATIC:
    {
    COLORREF dwColor; 

    dwColor = RGB(255, 0, 0);
    hDC = (HDC) wParam;

    //SetBkColor(hDC, dwColor);
    SetBkMode(hDC, TRANSPARENT);

    /*
    This is not going to work for child window
    SetWindowLong(
        hWnd, GWL_EXSTYLE,
        GetWindowLong((HWND)lParam, GWL_EXSTYLE) & ~WS_EX_LAYERED);

        SetLayeredWindowAttributes(
            (HWND)lParam, 0, 100, LWA_ALPHA);
        RedrawWindow((HWND)lParam, NULL, NULL, RDW_ERASE | RDW_INVALIDATE);
    */

    if (g_hBrushRed == NULL)
        g_hBrushRed = CreateSolidBrush(dwColor);
    }
    return (INT_PTR)g_hBrushRed;

回答1:

Why do you enable transparency with TRANSPARENT if you are going to return a valid brush for the background? You don't need SetBkMode and your red brush will be used by the control then.

来源：https://stackoverflow.com/questions/9643184/win32-gdi-set-opacity-of-static-control

标签

winapi

gdi

transparent