--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -2075,17 +2075,17 @@ public:
         return mFlags;
     }
 
     bool IsRightToLeft() const {
         return (Flags() & gfxTextRunFactory::TEXT_IS_RTL) != 0;
     }
 
     float GetDirection() const {
-        return IsRightToLeft() ? -1.0 : 1.0;
+        return IsRightToLeft() ? -1.0f : 1.0f;
     }
 
     bool DisableLigatures() const {
         return (Flags() & gfxTextRunFactory::TEXT_DISABLE_OPTIONAL_LIGATURES) != 0;
     }
 
     bool TextIs8Bit() const {
         return (Flags() & gfxTextRunFactory::TEXT_IS_8BIT) != 0;