Add a custom field renderer for checkout

src/pretix/presale/forms/renderers.py

@@ -0,0 +1,26 @@
+from bootstrap3.renderers import FieldRenderer
+from bootstrap3.utils import add_css_class
+
+
+class CheckoutFieldRenderer(FieldRenderer):
+    def __init__(self, *args, **kwargs):
+        kwargs['layout'] = 'horizontal'
+        super().__init__(*args, **kwargs)
+
+    def get_form_group_class(self):
+        form_group_class = self.form_group_class
+        if self.field.errors:
+            if self.error_css_class:
+                form_group_class = add_css_class(form_group_class, self.error_css_class)
+        else:
+            if self.field.form.is_bound:
+                form_group_class = add_css_class(form_group_class, self.success_css_class)
+        required = (getattr(self.field.field, '_show_required', False) or getattr(self.field.field, '_required', False) or self.field.field.required)
+        if required and self.required_css_class:
+            form_group_class = add_css_class(form_group_class, self.required_css_class)
+        if self.layout == 'horizontal':
+            form_group_class = add_css_class(
+                form_group_class,
+                self.get_size_class(prefix='form-group')
+            )
+        return form_group_class