[libadwaita/wip/exalm/tabs2] tab-box: Fix reordering with RTL

[Alexander Mikhaylenko <alexm src gnome org>]

commit d4c99c5366b8675961d97b97bcb7bf2a4038b25e
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Aug 2 12:08:36 2022 +0400

    tab-box: Fix reordering with RTL

 src/adw-tab-box.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/src/adw-tab-box.c b/src/adw-tab-box.c
index dfe58302..64a9c389 100644
--- a/src/adw-tab-box.c
+++ b/src/adw-tab-box.c
@@ -1321,7 +1321,12 @@ update_drag_reodering (AdwTabBox *self)
 
   for (l = self->tabs; l; l = l->next) {
     TabInfo *info = l->data;
-    int center = info->unshifted_pos + info->final_width / 2;
+    int center;
+
+    if (is_rtl)
+      center = info->unshifted_pos - info->final_width / 2;
+    else
+      center = info->unshifted_pos + info->final_width / 2;
 
     if (info == self->reordered_tab)
       old_index = i;