app: add "language" gimprc option and set the language accordingly

app/app.c

@@ -20,6 +20,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <locale.h>
 
 #ifdef HAVE_SYS_PARAM_H
 #include <sys/param.h>
@@ -64,9 +65,11 @@
 
 /*  local prototypes  */
 
-static void       app_init_update_none    (const gchar *text1,
+static void       app_init_update_noop    (const gchar *text1,
                                            const gchar *text2,
                                            gdouble      percentage);
+static void       app_init_language       (const gchar *language);
+
 static gboolean   app_exit_after_callback (Gimp        *gimp,
                                            gboolean     kill_it,
                                            GMainLoop   *loop);
@@ -183,6 +186,9 @@ app_run (const gchar         *full_prog_name,
 
   config = GIMP_BASE_CONFIG (gimp->config);
 
+  /*  change the locale if a language if specified  */
+  app_init_language (gimp->config->language);
+
   /*  initialize lowlevel stuff  */
   swap_is_ok = base_init (config, be_verbose, use_cpu_accel);
 
@@ -194,7 +200,7 @@ app_run (const gchar         *full_prog_name,
 #endif
 
   if (! update_status_func)
-    update_status_func = app_init_update_none;
+    update_status_func = app_init_update_noop;
 
   /*  Create all members of the global Gimp instance which need an already
    *  parsed gimprc, e.g. the data factories
@@ -258,10 +264,26 @@ app_run (const gchar         *full_prog_name,
 /*  private functions  */
 
 static void
-app_init_update_none (const gchar *text1,
+app_init_update_noop (const gchar *text1,
                       const gchar *text2,
                       gdouble      percentage)
 {
+  /*  deliberately do nothing  */
+}
+
+static void
+app_init_language (const gchar *language)
+{
+  /*  We already set the locale according to the environment, so just
+   *  return early if no language is set in gimprc.
+   */
+  if (! language)
+    return;
+
+  g_printerr ("Setting language to %s\n", language);
+
+  g_setenv ("LANGUAGE", language, TRUE);
+  setlocale (LC_ALL, "");
 }
 
 static gboolean

app/config/gimpcoreconfig.c

@@ -49,6 +49,7 @@
 enum
 {
   PROP_0,
+  PROP_LANGUAGE,
   PROP_INTERPOLATION_TYPE,
   PROP_PLUG_IN_PATH,
   PROP_MODULE_PATH,
@@ -133,6 +134,11 @@ gimp_core_config_class_init (GimpCoreConfigClass *klass)
   object_class->set_property = gimp_core_config_set_property;
   object_class->get_property = gimp_core_config_get_property;
 
+  GIMP_CONFIG_INSTALL_PROP_STRING (object_class, PROP_LANGUAGE,
+                                   "language", LANGUAGE_BLURB,
+                                   NULL,  /* take from environment */
+                                   GIMP_PARAM_STATIC_STRINGS |
+                                   GIMP_CONFIG_PARAM_RESTART);
   GIMP_CONFIG_INSTALL_PROP_ENUM (object_class, PROP_INTERPOLATION_TYPE,
                                  "interpolation-type",
                                  INTERPOLATION_TYPE_BLURB,
@@ -422,6 +428,7 @@ gimp_core_config_finalize (GObject *object)
 {
   GimpCoreConfig *core_config = GIMP_CORE_CONFIG (object);
 
+  g_free (core_config->language);
   g_free (core_config->plug_in_path);
   g_free (core_config->module_path);
   g_free (core_config->interpreter_path);
@@ -468,6 +475,10 @@ gimp_core_config_set_property (GObject      *object,
 
   switch (property_id)
     {
+    case PROP_LANGUAGE:
+      g_free (core_config->language);
+      core_config->language = g_value_dup_string (value);
+      break;
     case PROP_INTERPOLATION_TYPE:
       core_config->interpolation_type = g_value_get_enum (value);
       break;
@@ -652,6 +663,9 @@ gimp_core_config_get_property (GObject    *object,
 
   switch (property_id)
     {
+    case PROP_LANGUAGE:
+      g_value_set_string (value, core_config->language);
+      break;
     case PROP_INTERPOLATION_TYPE:
       g_value_set_enum (value, core_config->interpolation_type);
       break;

app/config/gimpcoreconfig.h

@@ -39,6 +39,7 @@ struct _GimpCoreConfig
 {
   GimpBaseConfig          parent_instance;
 
+  gchar                  *language;
   GimpInterpolationType   interpolation_type;
   gchar                  *plug_in_path;
   gchar                  *module_path;

app/config/gimprc-blurbs.h

@@ -198,6 +198,9 @@ N_("Sets the level of interpolation used for scaling and other " \
 #define INTERPRETER_PATH_BLURB \
 "Sets the interpreter search path."
 
+#define LANGUAGE_BLURB \
+N_("Specifies the language to use.")
+
 #define LAST_OPENED_SIZE_BLURB \
 N_("How many recently opened image filenames to keep on the File menu.")
 

app/main.c

@@ -615,6 +615,12 @@ gimp_init_malloc (void)
 static void
 gimp_init_i18n (void)
 {
+  /*  We may change the locale later if the user specifies a language
+   *  in the gimprc file. Here we are just initializing the locale
+   *  according to the environment variables and set up the paths to
+   *  the message catalogs.
+   */
+
   setlocale (LC_ALL, "");
 
   bindtextdomain (GETTEXT_PACKAGE"-libgimp", gimp_locale_directory ());