Win32APIでCEFのオフスクリーンレンダリング　キーボード入力

/////////////////////////////////////////////////////////////////////////
// キー修飾フラグ変換
int GetCefKeyboardModifiers(WPARAM wparam, LPARAM lparam) {
    int modifiers = 0;

    // 押下状態
    if (GetKeyState(VK_SHIFT) & 0x8000)   modifiers |= EVENTFLAG_SHIFT_DOWN;
    if (GetKeyState(VK_CONTROL) & 0x8000) modifiers |= EVENTFLAG_CONTROL_DOWN;
    if (GetKeyState(VK_MENU) & 0x8000)    modifiers |= EVENTFLAG_ALT_DOWN;

    // Lock 状態
    if (GetKeyState(VK_CAPITAL) & 1)  modifiers |= EVENTFLAG_CAPS_LOCK_ON;
    if (GetKeyState(VK_NUMLOCK) & 1)  modifiers |= EVENTFLAG_NUM_LOCK_ON;

    // 左右キー
    switch (wparam) {
    case VK_LSHIFT:
    case VK_LCONTROL:
    case VK_LMENU:
        modifiers |= EVENTFLAG_IS_LEFT;
        break;
    case VK_RSHIFT:
    case VK_RCONTROL:
    case VK_RMENU:
        modifiers |= EVENTFLAG_IS_RIGHT;
        break;
    default:
        break;
    }

    // 拡張ビット (bit 24)
    const bool extended = (lparam & 0x01000000) != 0;

    // テンキー判定
    if ((wparam >= VK_NUMPAD0 && wparam <= VK_NUMPAD9) ||
        wparam == VK_DECIMAL || wparam == VK_ADD || wparam == VK_SUBTRACT ||
        wparam == VK_MULTIPLY || wparam == VK_DIVIDE) {
        modifiers |= EVENTFLAG_IS_KEY_PAD;
    }
    else if (wparam == VK_RETURN) {
        // Enter: Numpad Enter なら extended が true（Winで Numpad Enter は拡張付き）
        if (extended) modifiers |= EVENTFLAG_IS_KEY_PAD;
    }


    return modifiers;
}

// キー入力
void OnKeyDown(HWND hwnd, UINT msg, int wp,int lp) {
    MyHandler* handler = (MyHandler*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
    CefKeyEvent ev{};
    ev.type = KEYEVENT_RAWKEYDOWN;
    ev.windows_key_code = (int)wp;
    ev.native_key_code = (int)lp;
    ev.is_system_key = (msg == WM_SYSKEYDOWN);
    ev.modifiers = GetCefKeyboardModifiers(wp, lp);
        /* Ctrl/Shift/Alt を反映 */;
    handler->GetBrowser()->GetHost()->SendKeyEvent(ev);
}
void OnKeyUp(HWND hwnd, UINT msg, int wp, int lp) {
    MyHandler* handler = (MyHandler*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
    CefKeyEvent ev{};
    ev.type = KEYEVENT_KEYUP;
    ev.windows_key_code = (int)wp;
    ev.native_key_code = (int)lp;
    ev.is_system_key = (msg == WM_SYSKEYUP);
    ev.modifiers = GetCefKeyboardModifiers(wp, lp);
    handler->GetBrowser()->GetHost()->SendKeyEvent(ev);
}
void OnChar(HWND hwnd, UINT msg, int wp, int lp) {
    MyHandler* handler = (MyHandler*)GetWindowLongPtr(hwnd, GWLP_USERDATA);
    CefKeyEvent ev;
    ev.type = KEYEVENT_CHAR;
    ev.character = static_cast<wchar_t>(wp);            // 入力文字
    ev.unmodified_character = static_cast<wchar_t>(wp); // 修飾なし
    ev.windows_key_code = static_cast<int>(wp);         // 互換目的
    ev.modifiers = GetCefKeyboardModifiers(wp, lp);
    handler->GetBrowser()->GetHost()->SendKeyEvent(ev);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp) {
    MyHandler* handler = nullptr;
    LPCREATESTRUCT pcs;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (msg) {
    case WM_CLOSE:

        OnClose(hwnd);
        DestroyWindow(hwnd);

        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        OnPaint(hwnd, hdc);
        EndPaint(hwnd, &ps);
        return 0;

    case WM_CREATE:

        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    case WM_MOUSEMOVE:
        OnMouseMove(hwnd, GET_X_LPARAM(lp), GET_Y_LPARAM(lp));
        return 0;
    case WM_LBUTTONDOWN:
        OnLButtonDown(hwnd, GET_X_LPARAM(lp), GET_Y_LPARAM(lp));
        return 0;
    case WM_LBUTTONUP:
        OnLButtonUp(hwnd, GET_X_LPARAM(lp), GET_Y_LPARAM(lp));
        return 0;

    case WM_KEYDOWN:
    case WM_SYSKEYDOWN:
        OnKeyDown(hwnd,msg,wp,lp); // キーダウン
        return 0;
    case WM_KEYUP:
    case WM_SYSKEYUP:
        OnKeyUp(hwnd, msg, wp, lp); // キーアップ
        return 0;
    case WM_CHAR:
        OnChar(hwnd, msg, wp, lp); // 文字入力
        return 0;
    }

    return DefWindowProc(hwnd, msg, wp, lp);
}