1 files changed, 7 insertions, 0 deletions
diff --git a/src/components/util/geometry.rs b/src/components/util/geometry.rs
index febb33660f4..ed0dcd5c420 100644
--- a/src/components/util/geometry.rs
+++ b/src/components/util/geometry.rs
@@ -7,6 +7,7 @@ use geom::rect::Rect;
 use geom::size::Size2D;
 
 use std::num::{NumCast, One, Zero};
+use std::fmt;
 
 pub struct Au(i32);
 
@@ -18,6 +19,12 @@ impl Clone for Au {
     }
 }
 
+impl fmt::Default for Au {
+    fn fmt(obj: &Au, f: &mut fmt::Formatter) {
+        write!(f.buf, "Au({})", *obj);
+    }
+}
+
 impl Eq for Au {
     #[inline]
     fn eq(&self, other: &Au) -> bool {