clutter: Avoid string translation to find text direction

Use Pango and Harfbuzz for the task, getting the default language,
then its scripts, then their directions. We pick the first valid
horizontal direction, resorting to LTR as a fallback.

Related: https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/5385
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2780>

clutter/clutter/clutter-main.c

@@ -51,6 +51,7 @@
 
 #include <stdlib.h>
 #include <glib/gi18n-lib.h>
+#include <hb-glib.h>
 
 #include "clutter-actor-private.h"
 #include "clutter-backend-private.h"
@@ -221,20 +222,28 @@ clutter_get_text_direction (void)
     }
   else
     {
-      /*
-       * Translate to default:RTL if you want your widgets
-       * to be RTL, otherwise translate to default:LTR.
-       * Do *not* translate it to "predefinito:LTR", if it
-       * it isn't default:LTR or default:RTL it will not work
-       */
-      const char *e = _("default:LTR");
+      PangoLanguage *language;
+      const PangoScript *scripts;
+      int n_scripts, i;
 
-      if (strcmp (e, "default:RTL") == 0)
-        dir = CLUTTER_TEXT_DIRECTION_RTL;
-      else if (strcmp (e, "default:LTR") == 0)
-        dir = CLUTTER_TEXT_DIRECTION_LTR;
-      else
-        g_warning ("Whoever translated default:LTR did so wrongly.");
+      language = pango_language_get_default ();
+      scripts = pango_language_get_scripts (language, &n_scripts);
+
+      for (i = 0; i < n_scripts; i++)
+        {
+          hb_script_t script;
+          hb_direction_t text_dir;
+
+          script = hb_glib_script_to_script ((GUnicodeScript) scripts[i]);
+          text_dir = hb_script_get_horizontal_direction (script);
+
+          if (text_dir == HB_DIRECTION_LTR)
+            dir = CLUTTER_TEXT_DIRECTION_LTR;
+          else if (text_dir == HB_DIRECTION_RTL)
+            dir = CLUTTER_TEXT_DIRECTION_RTL;
+          else
+            continue;
+        }
     }
 
   CLUTTER_NOTE (MISC, "Text direction: %s",

clutter/meson.build

@@ -36,6 +36,7 @@ clutter_pkg_deps = [
   gio_dep,
   json_glib_dep,
   pango_dep,
+  harfbuzz_dep,
 ]
 
 clutter_pkg_private_deps = [

meson.build

@@ -38,6 +38,7 @@ libstartup_notification_req = '>= 0.7'
 libcanberra_req = '>= 0.26'
 libwacom_req = '>= 0.13'
 atk_req = '>= 2.5.3'
+harfbuzz_req = '>= 2.6'
 
 # optional version requirements
 udev_req = '>= 228'
@@ -128,6 +129,7 @@ atk_dep = dependency('atk', version: atk_req)
 dbus_dep = dependency('dbus-1')
 colord_dep = dependency('colord', version: colord_req)
 lcms2_dep = dependency('lcms2', version: lcms2_req)
+harfbuzz_dep = dependency('harfbuzz', version: harfbuzz_req)
 
 have_wayland = get_option('wayland')
 # For now always require X11 support

po/POTFILES.in

@@ -11,7 +11,6 @@ src/backends/meta-input-settings.c
 src/backends/meta-monitor.c
 src/backends/meta-monitor-manager.c
 src/backends/x11/meta-clutter-backend-x11.c
-src/clutter/clutter/clutter-main.c
 src/compositor/compositor.c
 src/compositor/meta-background.c
 src/core/bell.c