The outline font manager provides support for the rendering of font outlines to bitmaps for screen and printer use, employing anti-aliasing for on-screen fonts, utilising sub-pixel anti-aliasing and caching for small font sizes. RISC OS was the first operating system to include such a feature, with it being previewed in early 1989 and included in RISC OS 2, launched in April 1989. Since 1994, in RISC OS 3.5, it has been possible to use an outline anti-aliased font in the WindowManager for UI elements, rather than the bitmap system font from previous versions.