ime: Add builtin handling of dead keys

The IME input method has been both ignoring keypresses of
non-spacing characters (ditching these as non displayable),
and not letting IME do anything about those.

Even though, the sparse documentation on IMM/IME seems to
hint that applications can't pipe non-spacing characters to
the input method manager, and experimentation shown that
those characters are indeed handled differently than how
it'd be expected.

Then, add basic handling of dead keys on the IME input method
itself , as it's not mutually exclusive with regular keymaps
with dead keys.

https://bugzilla.gnome.org/show_bug.cgi?id=704937

diff --git a/modules/input/gtkimcontextime.c b/modules/input/gtkimcontextime.c
index aa7f9a886cbfbefaec78d699d7858fa01a8170af..0de1b53daed75f2f732f73c1202bc3a1696f49e6 100644 (file)
--- a/modules/input/gtkimcontextime.c
+++ b/modules/input/gtkimcontextime.c
@@ -31,6 +31,7 @@
 
 #include "imm-extra.h"
 
+#include <gdk/gdkkeysyms.h>
 #include "gdk/win32/gdkwin32.h"
 #include "gdk/gdkkeysyms.h"
 
@@ -49,6 +50,9 @@
 
 /* #define BUFSIZE 4096 */
 
+#define IS_DEAD_KEY(k) \
+    ((k) >= GDK_dead_grave && (k) <= (GDK_dead_dasia+1))
+
 #define FREE_PREEDIT_BUFFER(ctx) \
 {                                \
   g_free((ctx)->priv->comp_str); \
@@ -70,6 +74,8 @@ struct _GtkIMContextIMEPrivate
   DWORD comp_str_len;
   LPVOID read_str;
   DWORD read_str_len;
+
+  guint32 dead_key_keyval;
 };
 
 
@@ -298,6 +304,64 @@ gtk_im_context_ime_set_client_window (GtkIMContext *context,
   context_ime->client_window = client_window;
 }
 
+static gunichar
+_gtk_im_context_ime_dead_key_unichar (guint    keyval,
+                                      gboolean spacing)
+{
+  switch (keyval)
+    {
+#define CASE(keysym, unicode, spacing_unicode) \
+      case GDK_dead_##keysym: return (spacing) ? spacing_unicode : unicode;
+
+      CASE (grave, 0x0300, 0x0060);
+      CASE (acute, 0x0301, 0x00b4);
+      CASE (circumflex, 0x0302, 0x005e);
+      CASE (tilde, 0x0303, 0x007e);    /* Also used with perispomeni, 0x342. */
+      CASE (macron, 0x0304, 0x00af);
+      CASE (breve, 0x0306, 0x02d8);
+      CASE (abovedot, 0x0307, 0x02d9);
+      CASE (diaeresis, 0x0308, 0x00a8);
+      CASE (hook, 0x0309, 0);
+      CASE (abovering, 0x030A, 0x02da);
+      CASE (doubleacute, 0x030B, 0x2dd);
+      CASE (caron, 0x030C, 0x02c7);
+      CASE (abovecomma, 0x0313, 0);         /* Equivalent to psili */
+      CASE (abovereversedcomma, 0x0314, 0); /* Equivalent to dasia */
+      CASE (horn, 0x031B, 0);  /* Legacy use for psili, 0x313 (or 0x343). */
+      CASE (belowdot, 0x0323, 0);
+      CASE (cedilla, 0x0327, 0x00b8);
+      CASE (ogonek, 0x0328, 0);        /* Legacy use for dasia, 0x314.*/
+      CASE (iota, 0x0345, 0);
+
+#undef CASE
+    default:
+      return 0;
+    }
+}
+
+static void
+_gtk_im_context_ime_commit_unichar (GtkIMContextIME *context_ime,
+                                    gunichar         c)
+{
+  gchar utf8[10];
+  int len;
+
+  if (context_ime->priv->dead_key_keyval != 0)
+    {
+      gunichar combining;
+
+      combining =
+        _gtk_im_context_ime_dead_key_unichar (context_ime->priv->dead_key_keyval,
+                                              FALSE);
+      g_unichar_compose (c, combining, &c);
+    }
+
+  len = g_unichar_to_utf8 (c, utf8);
+  utf8[len] = 0;
+
+  g_signal_emit_by_name (context_ime, "commit", utf8);
+  context_ime->priv->dead_key_keyval = 0;
+}
 
 static gboolean
 gtk_im_context_ime_filter_keypress (GtkIMContext *context,
@@ -324,16 +388,39 @@ gtk_im_context_ime_filter_keypress (GtkIMContext *context,
   if (!GDK_IS_WINDOW (context_ime->client_window))
     return FALSE;
 
+  if (event->keyval == GDK_space &&
+      context_ime->priv->dead_key_keyval != 0)
+    {
+      c = _gtk_im_context_ime_dead_key_unichar (context_ime->priv->dead_key_keyval, TRUE);
+      context_ime->priv->dead_key_keyval = 0;
+      _gtk_im_context_ime_commit_unichar (context_ime, c);
+      return TRUE;
+    }
+
   c = gdk_keyval_to_unicode (event->keyval);
+
   if (c)
     {
-      guchar utf8[10];
-      int len = g_unichar_to_utf8 (c, utf8);
-      utf8[len] = 0;
-
-      g_signal_emit_by_name (context_ime, "commit", utf8);
+      _gtk_im_context_ime_commit_unichar (context_ime, c);
       retval = TRUE;
     }
+  else if (IS_DEAD_KEY (event->keyval))
+    {
+      gunichar dead_key;
+
+      dead_key = _gtk_im_context_ime_dead_key_unichar (event->keyval, FALSE);
+
+      /* Emulate double input of dead keys */
+      if (dead_key && event->keyval == context_ime->priv->dead_key_keyval)
+        {
+          c = _gtk_im_context_ime_dead_key_unichar (context_ime->priv->dead_key_keyval, TRUE);
+          context_ime->priv->dead_key_keyval = 0;
+          _gtk_im_context_ime_commit_unichar (context_ime, c);
+          _gtk_im_context_ime_commit_unichar (context_ime, c);
+        }
+      else
+        context_ime->priv->dead_key_keyval = event->keyval;
+    }
 
   return retval;
 }