[cef] adjust windows code

While view framework used - hide window before it appears

Author: linev

gui/cefdisplay/src/RCefWebDisplayHandle.cxx

@@ -134,21 +134,26 @@ std::unique_ptr<ROOT::RWebDisplayHandle> RCefWebDisplayHandle::CefCreator::Displ
    bool supress_log = (settings.log_severity == LOGSEVERITY_DISABLE) ||
                       (settings.log_severity == LOGSEVERITY_FATAL);
 
-#ifdef OS_WIN
-   CefMainArgs main_args(GetModuleHandle(nullptr));
-#else
    TApplication *root_app = gROOT->GetApplication();
 
    std::vector<const char *> cef_argv = { root_app->Argv(0) };
 
+#ifdef OS_WIN
+
+   CefMainArgs main_args(args.IsHeadless() ? (HINSTANCE) 0 : GetModuleHandle(nullptr));
+
+#else
+
    if (args.IsHeadless()) {
       cef_argv.emplace_back("--user-data-dir=.");
       cef_argv.emplace_back("--allow-file-access-from-files");
       cef_argv.emplace_back("--disable-web-security");
       cef_argv.emplace_back("--disable-gpu");
       cef_argv.emplace_back("--ignore-gpu-blocklist");
+#ifdef OS_LINUX
       cef_argv.emplace_back("--use-gl=swiftshader");
       cef_argv.emplace_back("--enable-unsafe-swiftshader");
+#endif
       cef_argv.emplace_back("--off-screen-rendering-enabled");
       if (use_views)
          cef_argv.emplace_back("--ozone-platform=headless");
@@ -163,6 +168,7 @@ std::unique_ptr<ROOT::RWebDisplayHandle> RCefWebDisplayHandle::CefCreator::Displ
    cef_argv.emplace_back(nullptr);
 
    CefMainArgs main_args(cef_argv.size() - 1, (char **) cef_argv.data());
+
 #endif
 
    // CEF applications have multiple sub-processes (render, plugin, GPU, etc)

gui/cefdisplay/src/simple_app.cxx

@@ -44,22 +44,26 @@ namespace {
 // implementation for the CefWindow that hosts the Views-based browser.
 class SimpleWindowDelegate : public CefWindowDelegate {
    CefRefPtr<CefBrowserView> fBrowserView;
-   int fWidth{800};  ///< preferred window width
-   int fHeight{600}; ///< preferred window height
+   int fWidth = 800;  ///< preferred window width
+   int fHeight = 600; ///< preferred window height
+   bool fBatch = false;
 public:
-   explicit SimpleWindowDelegate(CefRefPtr<CefBrowserView> browser_view, int width = 800, int height = 600)
-      : fBrowserView(browser_view), fWidth(width), fHeight(height)
+   explicit SimpleWindowDelegate(CefRefPtr<CefBrowserView> browser_view, int width = 800, int height = 600, bool batch = false)
+      : fBrowserView(browser_view), fWidth(width), fHeight(height), fBatch(batch)
    {
    }
 
    void OnWindowCreated(CefRefPtr<CefWindow> window) override
    {
-      // Add the browser view and show the window.
       window->AddChildView(fBrowserView);
-      window->Show();
 
-      // Give keyboard focus to the browser view.
-      fBrowserView->RequestFocus();
+      if (fBatch) {
+         window->Hide();
+      } else {
+         window->Show();
+         // Give keyboard focus to the browser view.
+         fBrowserView->RequestFocus();
+      }
    }
 
    void OnWindowDestroyed(CefRefPtr<CefWindow> window) override { fBrowserView = nullptr; }
@@ -202,7 +206,7 @@ void SimpleApp::StartWindow(THttpServer *serv, const std::string &addr, const st
          CefBrowserView::CreateBrowserView(fGuiHandler, url, browser_settings, nullptr, nullptr, new SimpleBrowserViewDelegate());
 
       // Create the Window. It will show itself after creation.
-      CefWindow::CreateTopLevelWindow(new SimpleWindowDelegate(browser_view, rect.width, rect.height));
+      CefWindow::CreateTopLevelWindow(new SimpleWindowDelegate(browser_view, rect.width, rect.height, is_batch));
 
       if (fNextHandle) {
          fNextHandle->SetBrowser(browser_view->GetBrowser());
@@ -217,13 +221,14 @@ void SimpleApp::StartWindow(THttpServer *serv, const std::string &addr, const st
       // one should implement CefRenderHandler
 
       #if defined(OS_WIN)
-         RECT wnd_rect = {rect.x, rect.y, rect.x + rect.width, rect.y + rect.height};
-         if (!rect.IsEmpty()) window_info.SetAsChild(0, wnd_rect);
+         if (!rect.IsEmpty())
+            window_info.SetAsChild(0, rect);
          // On Windows we need to specify certain flags that will be passed to
          // CreateWindowEx().
          window_info.SetAsPopup(0, "cefsimple");
          if (is_batch)
-            window_info.SetAsWindowless(GetDesktopWindow());
+            // window_info.SetAsWindowless(GetDesktopWindow());
+            window_info.SetAsWindowless(kNullWindowHandle);
       #else
          if (!rect.IsEmpty())
             window_info.SetAsChild(0, rect);