> Microsoft Windows does not release any OpenType fonts natively (but has the DLL because) third-party applications could install them.
I'm not sure about Windows itself, but I know for a fact that Office includes at least one OpenType font: Cambria Math. It relies on the OpenType math typesetting information (which was largely designed by Microsoft). In addition, TrueType's layout information in not sophisticated enough for many languages (e.g. Arabic), so these users are most certainly using OpenType fonts.
I imagine that Microsoft have their own code for handling the OpenType layout tables, given that they co-developed them. OpenType fonts come in two flavours, PostScript and TrueType, depending on which format the glyph outlines use. Microsoft only ships fonts with TrueType outlines. The PostScript outlines are in CFF format, which is an Adobe technology. I expect that the Adobe code is responsible for dealing with them, especially as there is no published standard describing how to rasterize PostScript fonts with pixel accuracy.
The OT spec is the definitive document: https://www.microsoft.com/typography/otspec/otff.htm Look at the list of font tables, OpenType supports everything, but the individual formats are (to oversimplify), as follows:
- TTF = Required Tables + Tables Related to TrueType Outlines
- PostScript Flavor OTF = Required Tables + Tables Related to PostScript Outlines + Advanced Typographic Tables
- TrueType Flavor OTF = Required Tables + Tables Related to TrueType Outlines + Advanced Typographic Tables
Note that in a PostScript flavor OTF the glyph outlines are simply an entire Adobe CFF font embedded in a table. CFF is in turn a compact representation of a PostScript Type 1 font. There's an entire CFF spec too: https://partners.adobe.com/public/developer/en/font/5176.CFF...
I'm not sure about Windows itself, but I know for a fact that Office includes at least one OpenType font: Cambria Math. It relies on the OpenType math typesetting information (which was largely designed by Microsoft). In addition, TrueType's layout information in not sophisticated enough for many languages (e.g. Arabic), so these users are most certainly using OpenType fonts.