[gtk+/gtk-3-2] gdk: exclude MOD1 from the virtual modifier mapping

[Michael Natterer <mitch src gnome org>]

commit 273283db9217960970810e90ef841f685231484a
Author: Michael Natterer <mitch gimp org>
Date:   Mon Nov 7 20:09:00 2011 +0100

    gdk: exclude MOD1 from the virtual modifier mapping
    
    which effectively nails down the MOD1 == ALT assumption that is valid
    in all other parts of GTK+. After the modifier abstraction fixes for
    OSX, the virtual mapping is now (correctly) used in more places, and
    caused problems with the common default PC keyboard layout on X11 that
    colocates ALT and META on the same key.
    (cherry picked from commit ac943bf69a87c992cfde59c6720ef08fdd20e683)

 gdk/x11/gdkkeys-x11.c |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)
---
diff --git a/gdk/x11/gdkkeys-x11.c b/gdk/x11/gdkkeys-x11.c
index 5b7295b..80bf711 100644
--- a/gdk/x11/gdkkeys-x11.c
+++ b/gdk/x11/gdkkeys-x11.c
@@ -1489,13 +1489,12 @@ _gdk_x11_keymap_add_virt_mods (GdkKeymap       *keymap,
   keymap = GET_EFFECTIVE_KEYMAP (keymap);
   keymap_x11 = GDK_X11_KEYMAP (keymap);
 
-  for (i = 3; i < 8; i++)
+  /* See comment in add_virtual_modifiers() */
+  for (i = 4; i < 8; i++)
     {
       if ((1 << i) & *modifiers)
         {
-          if (keymap_x11->modmap[i] & GDK_MOD1_MASK)
-            *modifiers |= GDK_MOD1_MASK;
-          else if (keymap_x11->modmap[i] & GDK_SUPER_MASK)
+          if (keymap_x11->modmap[i] & GDK_SUPER_MASK)
             *modifiers |= GDK_SUPER_MASK;
           else if (keymap_x11->modmap[i] & GDK_HYPER_MASK)
             *modifiers |= GDK_HYPER_MASK;
@@ -1515,12 +1514,16 @@ gdk_x11_keymap_add_virtual_modifiers (GdkKeymap       *keymap,
   keymap = GET_EFFECTIVE_KEYMAP (keymap);
   keymap_x11 = GDK_X11_KEYMAP (keymap);
 
-  for (i = 3; i < 8; i++)
+  /*  This loop used to start at 3, which included MOD1 in the
+   *  virtual mapping. However, all of GTK+ treats MOD1 as a
+   *  synonym for Alt, and does not expect it to be mapped around,
+   *  therefore it's more sane to simply treat MOD1 like SHIFT and
+   *  CONTROL, which are not mappable either.
+   */
+  for (i = 4; i < 8; i++)
     {
       if ((1 << i) & *state)
         {
-          if (keymap_x11->modmap[i] & GDK_MOD1_MASK)
-            *state |= GDK_MOD1_MASK;
           if (keymap_x11->modmap[i] & GDK_SUPER_MASK)
             *state |= GDK_SUPER_MASK;
           if (keymap_x11->modmap[i] & GDK_HYPER_MASK)
@@ -1589,7 +1592,8 @@ gdk_x11_keymap_map_virtual_modifiers (GdkKeymap       *keymap,
     {
       if (*state & vmods[j])
         {
-          for (i = 3; i < 8; i++)
+          /* See comment in add_virtual_modifiers() */
+          for (i = 4; i < 8; i++)
             {
               if (keymap_x11->modmap[i] & vmods[j])
                 {