How to intercept mouse events?

[digory]

I need to track user activity (keyboard input, left and right mouse buttons, mouse wheel). For the keyboard, I can install a CefKeyboardHandler and implement OnKeyEvent. There does not seem to be a similar handler for mouse events, though. How can I intercept them?

[magreenblatt]

You can inject JavaScript into the page or use OS-specific hooks.

[digory]

Thanks for the reply. I can't use JavaScript, because a mouse event handler on the body tag does not see any mouse events whose propagation has been cancelled. I need to see *all* mouse events. Instead, I tried SetWindowsHookEx, but this is no good either, because it sees mouse events outside the browser window as well, even those in a different application. Finally, I tried SetWindowSubclass, which seems the way to go:

Code: Select all

LRESULT CALLBACK SubclassProc (HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass,
   DWORD_PTR dwRefData)
   {
   // Intercept events here.
   return ::DefSubclassProc (hwnd, uMsg, wParam, lParam);
   }

void KisCefClient::OnAfterCreated (CefRefPtr<CefBrowser> browser)
   {
   CEF_REQUIRE_UI_THREAD();

   HWND hwnd = browser->GetHost()->GetWindowHandle();
   HWND child = ::GetWindow (hwnd, GW_CHILD);

   if (child)
      {
      ::SetWindowSubclass (child, &SubclassProc, 0, 0);
      }
   }


The SubclassProc sees all kinds of events, but unfortunately, WM_LBUTTONDOWN is not seen.

[magreenblatt]

Use SetWindowHooksEx and compare the point against the browser bounding box.