diff --git a/libs/canvas/types.cc b/libs/canvas/types.cc
index 6d6d4e08c1..be5670716a 100644
--- a/libs/canvas/types.cc
+++ b/libs/canvas/types.cc
@@ -39,7 +39,60 @@ ArdourCanvas::operator<< (ostream & s, Duple const & r)
 ostream &
 ArdourCanvas::operator<< (ostream & s, Rect const & r)
 {
-	s << "[(" << r.x0 << ", " << r.y0 << "), (" << r.x1 << ", " << r.y1 << ") " << r.width() << " x " << r.height() << "]";
+	static const Coord BIG = COORD_MAX/10.0; /* 1 order of magnitude from COORD_MAX */
+
+	const Distance w = r.width();
+	const Distance h = r.height();
+
+	s << "[(";
+
+	if (r.x0 > BIG) {
+		s << "BIG";
+	} else {
+		s << r.x0;
+	}
+
+	s << ", ";
+
+	if (r.y0 > BIG) {
+		s << "BIG";
+	} else {
+		s << r.y0;
+	}
+
+	s << "), (";
+
+
+	if (r.x1 > BIG) {
+		s << "BIG";
+	} else {
+		s << r.x1;
+	}
+
+	s << ", ";
+
+	if (r.y1 > BIG) {
+		s << "BIG";
+	} else {
+		s << r.y1;
+	}
+
+	s << ") ";
+
+	if (w > BIG) {
+		s << "BIG";
+	} else {
+		s << w;
+	}
+
+	s << " x ";
+
+	if (h > BIG) {
+		s << "BIG";
+	} else {
+		s << h;
+	}
+
+	s << ']';
 	return s;
 }
-