CSize GetAspectRatioFilter() const;
Retrieves the setting for the current aspect-ratio filter. The aspect ratio is the ratio formed by a device's pixel width and height. Information about a device's aspect ratio is used in the creation, selection, and display of fonts. Windows provides a special filter, the aspect-ratio filter, to select fonts designed for a particular aspect ratio from all of the available fonts. The filter uses the aspect ratio specified by SetMapperFlags.
A CSize object representing the aspect ratio used by the current aspect-ratio filter.
CDC::SetMapperFlags, ::GetAspectRatioFilter, CSize