Implement support for grabbing the keyboard when in full screen mode.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4449 3789f03b-4d11-0410-bbf8-ca57d06f2519

1 files changed, 115 insertions, 0 deletions

diff --git a/vncviewer/win32.c b/vncviewer/win32.c
new file mode 100644
index 00000000..d75cc578
--- /dev/null
+++ b/vncviewer/win32.c
@@ -0,0 +1,115 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright 2011 Pierre Ossman <ossman@cendio.se> for Cendio AB
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#include <windows.h>
+
+static HANDLE thread;
+static DWORD thread_id;
+
+static HHOOK hook = 0;
+static HWND target_wnd = 0;
+
+static int is_system_hotkey(int vkCode) {
+  switch (vkCode) {
+  case VK_LWIN:
+  case VK_RWIN:
+  case VK_SNAPSHOT:
+    return 1;
+  case VK_TAB:
+    if (GetAsyncKeyState(VK_MENU) & 0x8000)
+      return 1;
+  case VK_ESCAPE:
+    if (GetAsyncKeyState(VK_MENU) & 0x8000)
+      return 1;
+    if (GetAsyncKeyState(VK_CONTROL) & 0x8000)
+      return 1;
+  }
+  return 0;
+}
+
+static LRESULT CALLBACK keyboard_hook(int nCode, WPARAM wParam, LPARAM lParam)
+{
+  if (nCode >= 0) {
+    KBDLLHOOKSTRUCT* msgInfo = (KBDLLHOOKSTRUCT*)lParam;
+
+    // Grabbing everything seems to mess up some keyboard state that
+    // FLTK relies on, so just grab the keys that we normally cannot.
+    if (is_system_hotkey(msgInfo->vkCode)) {
+      PostMessage(target_wnd, wParam, msgInfo->vkCode,
+                  (msgInfo->scanCode & 0xff) << 16 |
+                  (msgInfo->flags & 0xff) << 24);
+      return 1;
+    }
+  }
+
+  return CallNextHookEx(hook, nCode, wParam, lParam);
+}
+
+static DWORD WINAPI keyboard_thread(LPVOID data)
+{
+  MSG msg;
+
+  target_wnd = (HWND)data;
+
+  // Make sure a message queue is created
+  PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE | PM_NOYIELD);
+
+  hook = SetWindowsHookEx(WH_KEYBOARD_LL, keyboard_hook, GetModuleHandle(0), 0);
+  // If something goes wrong then there is not much we can do.
+  // Just sit around and wait for WM_QUIT...
+
+  while (GetMessage(&msg, NULL, 0, 0));
+
+  if (hook)
+    UnhookWindowsHookEx(hook);
+
+  target_wnd = 0;
+
+  return 0;
+}
+
+int win32_enable_lowlevel_keyboard(HWND hwnd)
+{
+  // Only one target at a time for now
+  if (thread != NULL) {
+    if (hwnd == target_wnd)
+      return 0;
+
+    return 1;
+  }
+
+  // We create a separate thread as it is crucial that hooks are processed
+  // in a timely manner.
+  thread = CreateThread(NULL, 0, keyboard_thread, hwnd, 0, &thread_id);
+  if (thread == NULL)
+    return 1;
+
+  return 0;
+}
+
+void win32_disable_lowlevel_keyboard(HWND hwnd)
+{
+  if (hwnd != target_wnd)
+    return;
+
+  PostThreadMessage(thread_id, WM_QUIT, 0, 0);
+
+  CloseHandle(thread);
+  thread = NULL;
+}