Issue #2545108: D7 Allow custom theme for /visitors path

forms/admin_settings.inc

@@ -170,5 +170,21 @@ function visitors_admin_settings() {
     '#description' => t('Chart height.'),
   );
 
+  $installed = array_filter(list_themes(), function ($obj) {
+    return $obj->status;
+  });
+
+  $themes = array('_admin' => t('admin'), '_default' => t('default')) + array_map(function ($value) {
+    return $value->name;
+  }, $installed);
+
+  $form['visitors_theme'] = array(
+    '#title' => t('Theme'),
+    '#description' => t('Select a theme for the Visitors reports.'),
+    '#type' => 'select',
+    '#options' => $themes,
+    '#default_value' => variable_get('visitors_theme', '_admin'),
+  );
+
   return system_settings_form($form);
 }