--- a/src/tools/common/template.py	Mon Oct 16 07:41:36 2017 +0200
+++ b/src/tools/common/template.py	Mon Oct 16 07:44:08 2017 +0200
@@ -196,6 +196,7 @@
         self.env.filters['next_gidx'] = self._next_gidx
         self.env.filters['cur_gidx'] = self._cur_gidx
         self.env.filters['date_days'] = self._date_days
+        self.env.filters['xmlui_class'] = self._xmlui_class
 
     def installTranslations(self):
         i18n_dir = os.path.join(self.base_dir, 'i18n')
@@ -328,6 +329,33 @@
     def _date_days(self, timestamp):
         return int(time.time() - int(timestamp))/(3600*24)
 
+    def attr_escape(self, text):
+        """escape a text to a value usable as an attribute
+
+        remove spaces, and put in lower case
+        """
+        return text.strip().lower().replace(' ', '_')
+
+    def _xmlui_class(self, xmlui_item, fields):
+        """return classes computed from XMLUI fields name
+
+        will return a string with a series of escaped {name}_{value} separated by spaces.
+        @param xmlui_item(xmlui.XMLUIPanel): XMLUI containing the widgets to use
+        @param fields(iterable(unicode)): names of the widgets to use
+        @return (unicode, None): computer string to use as class attribute value
+            None if no field was specified
+        """
+        classes = []
+        for name in fields:
+            escaped_name = self.attr_escape(name)
+            try:
+                for value in xmlui_item.widgets[name].values:
+                    classes.append(escaped_name + '_' + self.attr_escape(value))
+            except KeyError:
+                log.debug(_(u"ignoring field \"{name}\": it doesn't exists").format(name=name))
+                continue
+        return u' '.join(classes) or None
+
     def render(self, template, theme=None, locale=DEFAULT_LOCALE, root_path=u'', css_files=None, css_inline=False, **kwargs):
         """render a template