Change the window background color to the inactive color when the

window manager says the window isn't active.

ActiveWindowWatcher listens for X events and notifies the browser
windows when the active window changes.  We can't just use focus
events because popup menus cause browser windows to lose focus,
but it's still the "active" window.

Some window managers don't track active window, in which case we
don't get the x event and we just say that all windows are
active (our current behavior).

BUG=14649

Review URL: http://codereview.chromium.org/155303


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20313 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 57 insertions, 0 deletions

diff --git a/chrome/browser/gtk/active_window_watcher.cc b/chrome/browser/gtk/active_window_watcher.cc
new file mode 100644
index 0000000..5028b25
--- /dev/null
+++ b/chrome/browser/gtk/active_window_watcher.cc
@@ -0,0 +1,57 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <X11/Xlib.h>
+#include <gdk/gdk.h>
+#include <gdk/gdkx.h>
+
+#include "chrome/browser/gtk/active_window_watcher.h"
+#include "chrome/common/notification_service.h"
+
+ActiveWindowWatcher::ActiveWindowWatcher() {
+  Init();
+}
+
+void ActiveWindowWatcher::Init() {
+  // Set up X Event filter to listen for PropertyChange X events.  These events
+  // tell us when the active window changes.
+  GdkWindow* root = gdk_screen_get_root_window(gdk_screen_get_default());
+  gdk_window_add_filter(root, &ActiveWindowWatcher::OnWindowXEvent, this);
+  XSelectInput(GDK_WINDOW_XDISPLAY(root), GDK_WINDOW_XID(root),
+               PropertyChangeMask);
+}
+
+void ActiveWindowWatcher::NotifyActiveWindowChanged() {
+  GdkWindow* active_window = gdk_screen_get_active_window(
+      gdk_screen_get_default());
+
+  // If the window manager doesn't support _NET_ACTIVE_WINDOW, we don't know
+  // which window is active and just give up.
+  if (!active_window)
+    return;
+
+  NotificationService::current()->Notify(
+      NotificationType::ACTIVE_WINDOW_CHANGED,
+      Source<ActiveWindowWatcher>(this),
+      Details<const GdkWindow>(active_window));
+}
+
+GdkFilterReturn ActiveWindowWatcher::OnWindowXEvent(GdkXEvent* xevent,
+    GdkEvent* event, gpointer window_watcher) {
+  static const GdkAtom kNetActiveWindow = gdk_atom_intern(
+      "_NET_ACTIVE_WINDOW", FALSE);
+  static const Atom kNetActiveWindowAtom = gdk_x11_atom_to_xatom_for_display(
+        gdk_screen_get_display(gdk_screen_get_default()), kNetActiveWindow);
+
+  ActiveWindowWatcher* watcher = reinterpret_cast<ActiveWindowWatcher*>(
+      window_watcher);
+  XEvent* xev = static_cast<XEvent*>(xevent);
+
+  if (xev->xany.type == PropertyNotify &&
+      xev->xproperty.atom == kNetActiveWindowAtom) {
+    watcher->NotifyActiveWindowChanged();
+  }
+
+  return GDK_FILTER_CONTINUE;
+}