[gtk/fix-win10-emoji-panel-3-24] GDK-Win32: Support Windows 10 Emoji Panel better

[Chun-wei Fan <fanchunwei src gnome org>]

commit aab9cd02c8a53e518a912193cc68ed307563563c
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Tue Dec 10 16:56:07 2019 +0800

    GDK-Win32: Support Windows 10 Emoji Panel better
    
    When using the newer Windows 10 Emoji Panel to input Emoji, input is
    broken unless one is using Chinese, Korean or Japanese input methods
    (CJK IME), which means that it depends implicitly on the the Windows IME
    being active.
    
    Since there is no documented way to identify the Emoji Panel window,
    force IME to be activated when the Emoji Panel is activated via
    keystroke (WIN + '.' or WIN + ';') on Windows 10.  The "Entry"->"Entry
    Buffer" demo may not correctly reflect the character numbers when using
    the Emoji Panel, and preediting will be used in this case, but this
    seems like the best we can do for now.
    
    Fixes #2303.

 gdk/win32/gdkevents-win32.c          | 97 +++++++++++++++++++++++-------------
 gdk/win32/gdkwin32langnotification.c |  5 +-
 2 files changed, 66 insertions(+), 36 deletions(-)
---
diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
index 7aef277c27..de08151b6e 100644
--- a/gdk/win32/gdkevents-win32.c
+++ b/gdk/win32/gdkevents-win32.c
@@ -152,6 +152,7 @@ static int both_shift_pressed[2]; /* to store keycodes for shift keys */
 /* low-level keyboard hook handle */
 static HHOOK keyboard_hook = NULL;
 static UINT aerosnap_message;
+static UINT win10_emoji_panel_msg;
 
 static void
 track_mouse_event (DWORD dwFlags,
@@ -311,38 +312,39 @@ low_level_keystroke_handler (WPARAM message,
 
   if (message == WM_KEYDOWN &&
       !GDK_WINDOW_DESTROYED (toplevel) &&
-      _gdk_win32_window_lacks_wm_decorations (toplevel) && /* For CSD only */
       last_keydown != kbdhook->vkCode &&
       ((GetKeyState (VK_LWIN) & 0x8000) ||
       (GetKeyState (VK_RWIN) & 0x8000)))
-       {
-         GdkWin32AeroSnapCombo combo = GDK_WIN32_AEROSNAP_COMBO_NOTHING;
-         gboolean lshiftdown = GetKeyState (VK_LSHIFT) & 0x8000;
+    {
+      if (_gdk_win32_window_lacks_wm_decorations (toplevel)) /* For CSD only */
+        {
+          GdkWin32AeroSnapCombo combo = GDK_WIN32_AEROSNAP_COMBO_NOTHING;
+          gboolean lshiftdown = GetKeyState (VK_LSHIFT) & 0x8000;
           gboolean rshiftdown = GetKeyState (VK_RSHIFT) & 0x8000;
           gboolean oneshiftdown = (lshiftdown || rshiftdown) && !(lshiftdown && rshiftdown);
           gboolean maximized = gdk_window_get_state (toplevel) & GDK_WINDOW_STATE_MAXIMIZED;
 
-         switch (kbdhook->vkCode)
-           {
-           case VK_UP:
-             combo = GDK_WIN32_AEROSNAP_COMBO_UP;
-             break;
-           case VK_DOWN:
-             combo = GDK_WIN32_AEROSNAP_COMBO_DOWN;
-             break;
-           case VK_LEFT:
-             combo = GDK_WIN32_AEROSNAP_COMBO_LEFT;
-             break;
-           case VK_RIGHT:
-             combo = GDK_WIN32_AEROSNAP_COMBO_RIGHT;
-             break;
-           }
+          switch (kbdhook->vkCode)
+            {
+              case VK_UP:
+                combo = GDK_WIN32_AEROSNAP_COMBO_UP;
+                break;
+              case VK_DOWN:
+                combo = GDK_WIN32_AEROSNAP_COMBO_DOWN;
+                break;
+              case VK_LEFT:
+                combo = GDK_WIN32_AEROSNAP_COMBO_LEFT;
+                break;
+              case VK_RIGHT:
+                combo = GDK_WIN32_AEROSNAP_COMBO_RIGHT;
+                break;
+            }
 
-         if (oneshiftdown && combo != GDK_WIN32_AEROSNAP_COMBO_NOTHING)
-           combo += 4;
+          if (oneshiftdown && combo != GDK_WIN32_AEROSNAP_COMBO_NOTHING)
+            combo += 4;
 
-         /* These are the only combos that Windows WM does handle for us */
-         if (combo == GDK_WIN32_AEROSNAP_COMBO_SHIFTLEFT ||
+          /* These are the only combos that Windows WM does handle for us */
+          if (combo == GDK_WIN32_AEROSNAP_COMBO_SHIFTLEFT ||
               combo == GDK_WIN32_AEROSNAP_COMBO_SHIFTRIGHT)
             combo = GDK_WIN32_AEROSNAP_COMBO_NOTHING;
 
@@ -351,9 +353,24 @@ low_level_keystroke_handler (WPARAM message,
               g_win32_check_windows_version (6, 4, 0, G_WIN32_OS_ANY))
             combo = GDK_WIN32_AEROSNAP_COMBO_NOTHING;
 
-         if (combo != GDK_WIN32_AEROSNAP_COMBO_NOTHING)
+          if (combo != GDK_WIN32_AEROSNAP_COMBO_NOTHING)
             PostMessage (GDK_WINDOW_HWND (toplevel), aerosnap_message, (WPARAM) combo, 0);
-       }
+        }
+
+      /* Windows 10 only: support newer Emoji Panel: Force IME on!*/
+      if (g_win32_check_windows_version (6, 4, 0, G_WIN32_OS_ANY))
+        {
+          switch (kbdhook->vkCode)
+            {
+              case VK_OEM_PERIOD: /* '.' for all keyboards */
+              case VK_OEM_1: /* ';' on US-style keyboard layouts; not sure on other keyboard layouts... */
+                PostMessage (GDK_WINDOW_HWND (toplevel), win10_emoji_panel_msg, 0, 0);
+                break;
+              default:
+                break;
+            }
+        }
+    }
 
   if (message == WM_KEYDOWN)
     last_keydown = kbdhook->vkCode;
@@ -417,6 +434,7 @@ set_up_low_level_keyboard_hook (void)
     WIN32_API_FAILED ("SetWindowsHookEx");
 
   aerosnap_message = RegisterWindowMessage ("GDK_WIN32_AEROSNAP_MESSAGE");
+  win10_emoji_panel_msg = RegisterWindowMessage ("GDK_WIN32_WIN10_EMOJI_PANEL_MESSAGE");
 }
 
 void
@@ -2459,21 +2477,28 @@ gdk_event_translate (MSG  *msg,
     _gdk_win32_window_handle_aerosnap (gdk_window_get_toplevel (window),
                                        (GdkWin32AeroSnapCombo) msg->wParam);
 
-  switch (msg->message)
+  if (msg->message == WM_INPUTLANGCHANGE ||
+      msg->message == win10_emoji_panel_msg)
     {
-    case WM_INPUTLANGCHANGE:
       _gdk_input_locale = (HKL) msg->lParam;
-      _gdk_win32_keymap_set_active_layout (GDK_WIN32_KEYMAP (_gdk_win32_display_get_keymap (_gdk_display)), 
_gdk_input_locale);
+      _gdk_win32_keymap_set_active_layout (GDK_WIN32_KEYMAP (_gdk_win32_display_get_keymap (_gdk_display)),
+                                           _gdk_input_locale);
       GetLocaleInfo (MAKELCID (LOWORD (_gdk_input_locale), SORT_DEFAULT),
-                    LOCALE_IDEFAULTANSICODEPAGE,
-                    buf, sizeof (buf));
+                     LOCALE_IDEFAULTANSICODEPAGE,
+                     buf, sizeof (buf));
       _gdk_input_codepage = atoi (buf);
       _gdk_keymap_serial++;
       GDK_NOTE (EVENTS,
-               g_print (" cs:%lu hkl:%p%s cp:%d",
-                        (gulong) msg->wParam,
-                        (gpointer) msg->lParam, _gdk_input_locale_is_ime ? " (IME)" : "",
-                        _gdk_input_codepage));
+                g_print (" cs:%lu hkl:%p%s cp:%d",
+                         (gulong) msg->wParam,
+                         (gpointer) msg->lParam,
+                         _gdk_input_locale_is_ime ? " (IME)" : "",
+                         _gdk_input_codepage));
+
+      /* force the IME input on when using Windows 10 Emoji panel! */
+      if (msg->message == win10_emoji_panel_msg)
+        _gdk_input_locale_is_ime = TRUE;
+
       gdk_settings_notify (window, "gtk-im-module", GDK_SETTING_ACTION_CHANGED);
 
       /* Generate a dummy key event to "nudge" IMContext */
@@ -2491,8 +2516,10 @@ gdk_event_translate (MSG  *msg,
       event->key.is_modifier = FALSE;
       event->key.state = 0;
       _gdk_win32_append_event (event);
-      break;
+    }
 
+  switch (msg->message)
+    {
     case WM_SYSKEYUP:
     case WM_SYSKEYDOWN:
       GDK_NOTE (EVENTS,
diff --git a/gdk/win32/gdkwin32langnotification.c b/gdk/win32/gdkwin32langnotification.c
index 94814ecd6a..788ef229c4 100644
--- a/gdk/win32/gdkwin32langnotification.c
+++ b/gdk/win32/gdkwin32langnotification.c
@@ -90,7 +90,10 @@ alpn_sink_on_activated (ITfActiveLanguageProfileNotifySink *This,
                         REFGUID                             guidProfile,
                         BOOL                                fActivated)
 {
-  _gdk_input_locale_is_ime = fActivated;
+  /* clsid and guidProfile are both NULL during WM_INPUTLANGCHANGE */
+  if (clsid == NULL && guidProfile == NULL)
+    _gdk_input_locale_is_ime = fActivated;
+
   return S_OK;
 }