add disable-w32-ime function to emacs with Windows GUI

emacs-25.3-disable-w32-ime.diff

--- ./src/w32fns.c.orig	2017-04-15 00:02:47.000000000 +0900
+++ ./src/w32fns.c	2017-09-13 21:00:14.888905300 +0900
@@ -78,6 +78,8 @@
 extern const char *map_w32_filename (const char *, const char **);
 extern char * w32_strerror (int error_no);
 
+static int ime_disabled = 0;
+
 #ifndef IDC_HAND
 #define IDC_HAND MAKEINTRESOURCE(32649)
 #endif
@@ -154,6 +156,8 @@
 DECLARE_HANDLE(HMONITOR);
 #endif
 
+typedef HIMC (WINAPI * ImmAssociateContextEx_Proc) (IN HWND wnd, IN HIMC context, IN DWORD flags);
+
 typedef BOOL (WINAPI * TrackMouseEvent_Proc)
   (IN OUT LPTRACKMOUSEEVENT lpEventTrack);
 typedef LONG (WINAPI * ImmGetCompositionString_Proc)
@@ -174,6 +178,8 @@
 typedef BOOL (WINAPI * GetTitleBarInfo_Proc)
   (IN HWND hwnd, OUT TITLEBAR_INFO* info);
 
+ImmAssociateContextEx_Proc associate_contextex_fn = NULL;
+
 TrackMouseEvent_Proc track_mouse_event_fn = NULL;
 ImmGetCompositionString_Proc get_composition_string_fn = NULL;
 ImmGetContext_Proc get_ime_context_fn = NULL;
@@ -4350,6 +4356,11 @@
       goto dflt;
 
     case WM_SETFOCUS:
+      if (ime_disabled)
+        associate_contextex_fn (hwnd, 0, 0);
+      else
+        associate_contextex_fn (hwnd, 0, IACE_DEFAULT);
+
       dpyinfo->faked_key = 0;
       reset_modifiers ();
       register_hot_keys (hwnd);
@@ -4594,6 +4605,10 @@
       my_post_msg (&wmsg, hwnd, msg, wParam, lParam);
       return 1;
 
+    case WM_EMACS_IMM_ASSOCIATE_CONTEXT:
+      associate_contextex_fn (hwnd, 0, lParam);
+      break;
+
     default:
       /* Check for messages registered at runtime. */
       if (msg == msh_mousewheel)
@@ -7296,6 +7311,47 @@
 #endif /* WINDOWSNT */
 
 
+DEFUN ("disable-w32-ime", Fdisable_w32_ime, Sdisable_w32_ime,
+       0, 0, "", doc: /* Disable W32 IME.  */)
+  (void)
+{
+  struct frame *f = SELECTED_FRAME ();
+
+  if (f)
+    {
+      SendMessage (FRAME_W32_WINDOW (f), WM_EMACS_IMM_ASSOCIATE_CONTEXT,
+                   (WPARAM) 0, (LPARAM) 0);
+      ime_disabled = 1;
+    }
+
+  return Qnil;
+}
+
+DEFUN ("enable-w32-ime", Fenable_w32_ime, Senable_w32_ime,
+       0, 0, "", doc: /* Enable W32 IME.  */)
+  (void)
+{
+  struct frame *f = SELECTED_FRAME ();
+
+  if (f)
+    {
+      SendMessage (FRAME_W32_WINDOW (f), WM_EMACS_IMM_ASSOCIATE_CONTEXT,
+                   (WPARAM) 0, (LPARAM) IACE_DEFAULT);
+      ime_disabled = 0;
+    }
+
+  return Qnil;
+}
+DEFUN ("w32-ime-disabled-p", Fw32_ime_disabled_p, Sw32_ime_disabled_p,
+       0, 0, 0, doc: /* Return t if W32 IME is disabled.  */)
+  (void)
+{
+  if (ime_disabled)
+    return Qt;
+  else
+    return Qnil;
+}
+
 /***********************************************************************
 			 w32 specialized functions
  ***********************************************************************/
@@ -9652,6 +9708,10 @@
 
   /* W32 specific functions */
 
+  defsubr (&Sdisable_w32_ime);
+  defsubr (&Senable_w32_ime);
+  defsubr (&Sw32_ime_disabled_p);
+
   defsubr (&Sw32_define_rgb_color);
   defsubr (&Sw32_default_color_map);
   defsubr (&Sw32_display_monitor_attributes_list);
@@ -9924,6 +9984,11 @@
 globals_of_w32fns (void)
 {
   HMODULE user32_lib = GetModuleHandle ("user32.dll");
+  {
+    HMODULE imm32_lib = GetModuleHandle ("imm32.dll");
+    associate_contextex_fn = (ImmAssociateContextEx_Proc)
+      GetProcAddress (imm32_lib, "ImmAssociateContextEx");
+  }
   /*
     TrackMouseEvent not available in all versions of Windows, so must load
     it dynamically.  Do it once, here, instead of every time it is used.
--- ./src/w32term.h.orig	2017-04-15 00:02:47.000000000 +0900
+++ ./src/w32term.h	2017-09-13 21:00:14.896921900 +0900
@@ -636,6 +636,8 @@
 #define UNICODE_NOCHAR 0xFFFF
 #endif
 
+#define WM_EMACS_IMM_ASSOCIATE_CONTEXT (WM_USER+2400)
+
 #define WM_EMACS_START                 (WM_USER + 1)
 #define WM_EMACS_KILL                  (WM_EMACS_START + 0)
 #define WM_EMACS_CREATEWINDOW          (WM_EMACS_START + 1)