[mutter] wayland: Notify tablet mode switches

[Carlos Garnacho <carlosg src gnome org>]

commit 7e3fbfbdd2a67a9b6e00031aa3098da6facb1291
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Dec 28 12:10:23 2016 +0100

    wayland: Notify tablet mode switches
    
    This will show a fancy OSD so the change is immediately visible.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=771098

 src/backends/meta-input-settings.c |   20 ++++++++++++++++++++
 src/core/display.c                 |   25 +++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 0 deletions(-)
---
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index 166e728..bd3d848 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -1692,8 +1692,28 @@ meta_input_settings_handle_pad_button (MetaInputSettings           *input_settin
 
   pad = clutter_event_get_source_device ((ClutterEvent *) event);
   button = event->button;
+  mode = event->mode;
+  group = clutter_input_device_get_mode_switch_button_group (pad, button);
   is_press = event->type == CLUTTER_PAD_BUTTON_PRESS;
 
+  if (is_press && group >= 0)
+    {
+      guint n_modes = clutter_input_device_get_group_n_modes (pad, group);
+      const gchar *pretty_name = NULL;
+#ifdef HAVE_LIBWACOM
+      MetaInputSettingsPrivate *priv;
+      DeviceMappingInfo *info;
+
+      priv = meta_input_settings_get_instance_private (input_settings);
+      info = g_hash_table_lookup (priv->mappable_devices, pad);
+
+      if (info && info->wacom_device)
+        pretty_name = libwacom_get_name (info->wacom_device);
+#endif
+      meta_display_notify_pad_group_switch (meta_get_display (), pad,
+                                            pretty_name, group, mode, n_modes);
+    }
+
   action = meta_input_settings_get_pad_button_action (input_settings, pad, button);
 
   switch (action)
diff --git a/src/core/display.c b/src/core/display.c
index 372457f..080c328 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -3233,3 +3233,28 @@ meta_display_show_tablet_mapping_notification (MetaDisplay        *display,
   meta_display_show_osd (display, lookup_tablet_monitor (display, pad),
                          "input-tablet-symbolic", pretty_name);
 }
+
+void
+meta_display_notify_pad_group_switch (MetaDisplay        *display,
+                                      ClutterInputDevice *pad,
+                                      const gchar        *pretty_name,
+                                      guint               n_group,
+                                      guint               n_mode,
+                                      guint               n_modes)
+{
+  GString *message;
+  guint i;
+
+  if (!pretty_name)
+    pretty_name = clutter_input_device_get_device_name (pad);
+
+  message = g_string_new (pretty_name);
+  g_string_append_c (message, '\n');
+  for (i = 0; i < n_modes; i++)
+    g_string_append (message, (i == n_mode) ? "⚫" : "⚪");
+
+  meta_display_show_osd (display, lookup_tablet_monitor (display, pad),
+                         "input-tablet-symbolic", message->str);
+
+  g_string_free (message, TRUE);
+}