[util] List supported output formats in --help output
diff --git a/util/view-cairo.hh b/util/view-cairo.hh
index c621984..f273464 100644
--- a/util/view-cairo.hh
+++ b/util/view-cairo.hh
@@ -33,7 +33,7 @@
 
 struct view_cairo_t {
   view_cairo_t (option_parser_t *parser)
-	       : output_options (parser),
+	       : output_options (parser, helper_cairo_supported_formats),
 	         view_options (parser) {}
   ~view_cairo_t (void) {
     if (debug)