The OpenType™ format is a superset of the earlier TrueType and Adobe® PostScript® Type 1 font formats. As jointly defined by Microsoft and Adobe Systems, it is technically an extension of Microsoft's TrueType Open format, which can contain either PostScript font outlines or TrueType font outlines in a single font file that can be used on both Macintosh and Windows platforms. It can also include an expanded character set based on the Unicode encoding standard plus advanced typographic intelligence for glyph positioning and glyph substitution that allow for the inclusion of numerous alternate glyphs in one font file.