input-settings: Wire up middle-emulation

This allows emulating middle click via simultaneous left and right
click.  Fixes #238.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/256

src/backends/meta-input-settings-private.h

@@ -114,6 +114,17 @@ struct _MetaInputSettingsClass
                                   GDesktopStylusButtonAction  primary,
                                   GDesktopStylusButtonAction  secondary,
                                   GDesktopStylusButtonAction  tertiary);
+
+  void (* set_mouse_middle_click_emulation) (MetaInputSettings  *settings,
+                                             ClutterInputDevice *device,
+                                             gboolean            enabled);
+  void (* set_touchpad_middle_click_emulation) (MetaInputSettings  *settings,
+                                                ClutterInputDevice *device,
+                                                gboolean            enabled);
+  void (* set_trackball_middle_click_emulation) (MetaInputSettings  *settings,
+                                                 ClutterInputDevice *device,
+                                                 gboolean            enabled);
+
   gboolean (* has_two_finger_scroll) (MetaInputSettings  *settings,
                                       ClutterInputDevice *device);
   gboolean (* is_trackball_device) (MetaInputSettings  *settings,

src/backends/meta-input-settings.c

@@ -418,6 +418,39 @@ get_settings_for_device_type (MetaInputSettings      *input_settings,
     }
 }
 
+static void
+update_middle_click_emulation (MetaInputSettings  *input_settings,
+                               GSettings          *settings,
+                               ClutterInputDevice *device)
+{
+  ConfigBoolFunc func;
+  const gchar *key = "emulate-middle";
+  MetaInputSettingsPrivate *priv = meta_input_settings_get_instance_private (input_settings);
+
+  if (!settings)
+    return;
+
+  if (settings == priv->mouse_settings)
+    func = META_INPUT_SETTINGS_GET_CLASS (input_settings)->set_mouse_middle_click_emulation;
+  else if (settings == priv->touchpad_settings)
+    func = META_INPUT_SETTINGS_GET_CLASS (input_settings)->set_touchpad_middle_click_emulation;
+  else if (settings == priv->trackball_settings)
+    func = META_INPUT_SETTINGS_GET_CLASS (input_settings)->set_trackball_middle_click_emulation;
+  else
+    return;
+
+  if (device)
+    {
+      settings_device_set_bool_setting (input_settings, device, func,
+                                        g_settings_get_boolean (settings, key));
+    }
+  else
+    {
+      settings_set_bool_setting (input_settings, CLUTTER_POINTER_DEVICE, func,
+                                 g_settings_get_boolean (settings, key));
+    }
+}
+
 static void
 update_device_speed (MetaInputSettings      *input_settings,
                      ClutterInputDevice     *device)
@@ -1141,6 +1174,8 @@ meta_input_settings_changed_cb (GSettings  *settings,
         update_device_natural_scroll (input_settings, NULL);
       else if (strcmp (key, "accel-profile") == 0)
         update_pointer_accel_profile (input_settings, settings, NULL);
+      else if (strcmp (key, "middle-click-emulation") == 0)
+        update_middle_click_emulation (input_settings, settings, NULL);
     }
   else if (settings == priv->touchpad_settings)
     {
@@ -1164,6 +1199,8 @@ meta_input_settings_changed_cb (GSettings  *settings,
         update_touchpad_two_finger_scroll (input_settings, NULL);
       else if (strcmp (key, "click-method") == 0)
         update_touchpad_click_method (input_settings, NULL);
+      else if (strcmp (key, "middle-click-emulation") == 0)
+        update_middle_click_emulation (input_settings, settings, NULL);
     }
   else if (settings == priv->trackball_settings)
     {
@@ -1171,6 +1208,8 @@ meta_input_settings_changed_cb (GSettings  *settings,
         update_trackball_scroll_button (input_settings, NULL);
       else if (strcmp (key, "accel-profile") == 0)
         update_pointer_accel_profile (input_settings, settings, NULL);
+      else if (strcmp (key, "middle-click-emulation") == 0)
+        update_middle_click_emulation (input_settings, settings, NULL);
     }
   else if (settings == priv->keyboard_settings)
     {
@@ -1687,6 +1726,10 @@ apply_device_settings (MetaInputSettings  *input_settings,
                                 device);
   load_keyboard_a11y_settings (input_settings, device);
   load_pointer_a11y_settings (input_settings, device);
+
+  update_middle_click_emulation (input_settings, priv->mouse_settings, device);
+  update_middle_click_emulation (input_settings, priv->touchpad_settings, device);
+  update_middle_click_emulation (input_settings, priv->trackball_settings, device);
 }
 
 static void

src/backends/native/meta-input-settings-native.c

@@ -400,6 +400,13 @@ is_mouse_device (ClutterInputDevice *device)
           !has_udev_property (device, "ID_INPUT_POINTINGSTICK"));
 }
 
+static gboolean
+meta_input_settings_native_is_touchpad_device (MetaInputSettings  *settings,
+                                               ClutterInputDevice *device)
+{
+  return has_udev_property (device, "ID_INPUT_TOUCHPAD");
+}
+
 static gboolean
 meta_input_settings_native_is_trackball_device (MetaInputSettings  *settings,
                                                 ClutterInputDevice *device)
@@ -562,6 +569,60 @@ meta_input_settings_native_set_stylus_button_map (MetaInputSettings          *se
                                                  action_to_evcode (tertiary));
 }
 
+static void
+meta_input_settings_native_set_mouse_middle_click_emulation (MetaInputSettings  *settings,
+                                                             ClutterInputDevice *device,
+                                                             gboolean            enabled)
+{
+  struct libinput_device *libinput_device;
+
+  if (!is_mouse_device (device))
+    return;
+
+  libinput_device = meta_input_device_native_get_libinput_device (device);
+  if (!libinput_device)
+    return;
+
+  if (libinput_device_config_middle_emulation_is_available (libinput_device))
+    libinput_device_config_middle_emulation_set_enabled (libinput_device, enabled);
+}
+
+static void
+meta_input_settings_native_set_touchpad_middle_click_emulation (MetaInputSettings  *settings,
+                                                                ClutterInputDevice *device,
+                                                                gboolean            enabled)
+{
+  struct libinput_device *libinput_device;
+
+  if (!meta_input_settings_native_is_touchpad_device (settings, device))
+    return;
+
+  libinput_device = meta_input_device_native_get_libinput_device (device);
+  if (!libinput_device)
+    return;
+
+  if (libinput_device_config_middle_emulation_is_available (libinput_device))
+    libinput_device_config_middle_emulation_set_enabled (libinput_device, enabled);
+}
+
+static void
+meta_input_settings_native_set_trackball_middle_click_emulation (MetaInputSettings  *settings,
+                                                                 ClutterInputDevice *device,
+                                                                 gboolean            enabled)
+{
+  struct libinput_device *libinput_device;
+
+  if (!meta_input_settings_native_is_trackball_device (settings, device))
+    return;
+
+  libinput_device = meta_input_device_native_get_libinput_device (device);
+  if (!libinput_device)
+    return;
+
+  if (libinput_device_config_middle_emulation_is_available (libinput_device))
+    libinput_device_config_middle_emulation_set_enabled (libinput_device, enabled);
+}
+
 static void
 meta_input_settings_native_class_init (MetaInputSettingsNativeClass *klass)
 {
@@ -591,6 +652,10 @@ meta_input_settings_native_class_init (MetaInputSettingsNativeClass *klass)
   input_settings_class->set_stylus_pressure = meta_input_settings_native_set_stylus_pressure;
   input_settings_class->set_stylus_button_map = meta_input_settings_native_set_stylus_button_map;
 
+  input_settings_class->set_mouse_middle_click_emulation = meta_input_settings_native_set_mouse_middle_click_emulation;
+  input_settings_class->set_touchpad_middle_click_emulation = meta_input_settings_native_set_touchpad_middle_click_emulation;
+  input_settings_class->set_trackball_middle_click_emulation = meta_input_settings_native_set_trackball_middle_click_emulation;
+
   input_settings_class->has_two_finger_scroll = meta_input_settings_native_has_two_finger_scroll;
   input_settings_class->is_trackball_device = meta_input_settings_native_is_trackball_device;
 }

src/backends/x11/meta-input-settings-x11.c

@@ -512,6 +512,13 @@ is_mouse (MetaInputSettings  *settings,
           !has_udev_property (settings, device, "ID_INPUT_POINTINGSTICK"));
 }
 
+static gboolean
+meta_input_settings_x11_is_touchpad_device (MetaInputSettings  *settings,
+                                            ClutterInputDevice *device)
+{
+  return has_udev_property (settings, device, "ID_INPUT_TOUCHPAD");
+}
+
 static gboolean
 meta_input_settings_x11_is_trackball_device (MetaInputSettings  *settings,
                                              ClutterInputDevice *device)
@@ -820,6 +827,48 @@ meta_input_settings_x11_set_stylus_button_map (MetaInputSettings          *setti
     }
 }
 
+static void
+meta_input_settings_x11_set_mouse_middle_click_emulation (MetaInputSettings  *settings,
+                                                          ClutterInputDevice *device,
+                                                          gboolean            enabled)
+{
+  guchar value = enabled ? 1 : 0;
+
+  if (!is_mouse (settings, device))
+    return;
+
+  change_property (device, "libinput Middle Click Emulation Enabled",
+                   XA_INTEGER, 8, &value, 1);
+}
+
+static void
+meta_input_settings_x11_set_touchpad_middle_click_emulation (MetaInputSettings  *settings,
+                                                             ClutterInputDevice *device,
+                                                             gboolean            enabled)
+{
+  guchar value = enabled ? 1 : 0;
+
+  if (!meta_input_settings_x11_is_touchpad_device (settings, device))
+    return;
+
+  change_property (device, "libinput Middle Click Emulation Enabled",
+                   XA_INTEGER, 8, &value, 1);
+}
+
+static void
+meta_input_settings_x11_set_trackball_middle_click_emulation (MetaInputSettings  *settings,
+                                                              ClutterInputDevice *device,
+                                                              gboolean            enabled)
+{
+  guchar value = enabled ? 1 : 0;
+
+  if (!meta_input_settings_x11_is_trackball_device (settings, device))
+    return;
+
+  change_property (device, "libinput Middle Click Emulation Enabled",
+                   XA_INTEGER, 8, &value, 1);
+}
+
 static void
 meta_input_settings_x11_set_stylus_pressure (MetaInputSettings      *settings,
                                              ClutterInputDevice     *device,
@@ -864,6 +913,10 @@ meta_input_settings_x11_class_init (MetaInputSettingsX11Class *klass)
   input_settings_class->set_stylus_pressure = meta_input_settings_x11_set_stylus_pressure;
   input_settings_class->set_stylus_button_map = meta_input_settings_x11_set_stylus_button_map;
 
+  input_settings_class->set_mouse_middle_click_emulation = meta_input_settings_x11_set_mouse_middle_click_emulation;
+  input_settings_class->set_touchpad_middle_click_emulation = meta_input_settings_x11_set_touchpad_middle_click_emulation;
+  input_settings_class->set_trackball_middle_click_emulation = meta_input_settings_x11_set_trackball_middle_click_emulation;
+
   input_settings_class->has_two_finger_scroll = meta_input_settings_x11_has_two_finger_scroll;
   input_settings_class->is_trackball_device = meta_input_settings_x11_is_trackball_device;
 }