How to set SDL frame between wallpaper and wallpaper icon

main.cpp

/* if ur enviroment is Windows, import SDL2 and winapi
if ur enviroment is Linux or Unix, import SDL2 and X11/Xlib.h
*/

#if _WIN32 || _WIN64
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam) {
    HWND p = FindWindowEx(hwnd, NULL, "SHELLDLL_DefView", NULL);
    HWND* ret = (HWND*)lParam;

    if (p) {
        // Gets the WorkerW Window after the current one.
        *ret = FindWindowEx(NULL, hwnd, "WorkerW", NULL);
        }
    return true;
}

HWND get_wallpaper_window(){
    HWND progman = FindWindow("ProgMan", NULL);
    SendMessageTimeout(progman, 0x052C, 0, 0, SMTO_NORMAL, 1000, nullptr);
    HWND wallpaper_hwnd = nullptr;
    EnumWindows(EnumWindowsProc, (LPARAM)&wallpaper_hwnd);
    return wallpaper_hwnd;
}
#else 
Window get_wallpaper_window(){
    Display* x11d = XOpenDisplay(NULL);
    Window x11w = RootWindow(x11d, DefaultScreen(x11d));
    return x11w;
}
#endif