diff --git a/src/servers/app/drawing/Painter/Transformable.cpp b/src/servers/app/drawing/Painter/Transformable.cpp
index 308fad512a..ee801900f2 100644
--- a/src/servers/app/drawing/Painter/Transformable.cpp
+++ b/src/servers/app/drawing/Painter/Transformable.cpp
@@ -247,7 +247,7 @@ Transformable::InverseTransform(const BPoint& point) const
 
 // TransformBounds
 BRect
-Transformable::TransformBounds(BRect bounds) const
+Transformable::TransformBounds(const BRect& bounds) const
 {
 	if (bounds.IsValid()) {
 		BPoint lt(bounds.left, bounds.top);
diff --git a/src/servers/app/drawing/Painter/Transformable.h b/src/servers/app/drawing/Painter/Transformable.h
index b4c8a45385..7cf3d4999d 100644
--- a/src/servers/app/drawing/Painter/Transformable.h
+++ b/src/servers/app/drawing/Painter/Transformable.h
@@ -51,7 +51,7 @@ class Transformable : public BArchivable,
 
 								// transforms the rectangle "bounds" and
 								// returns the *bounding box* of that
-			BRect				TransformBounds(BRect bounds) const;
+			BRect				TransformBounds(const BRect& bounds) const;
 
 								// some convenience functions
 	virtual	void				TranslateBy(BPoint offset);