Fonts: Cairo: A Vector Graphics Library

## Fonts

Fonts are once more an area where there is a hierarchy of types:

    cairo_font_face_t
       cairo_ft_font_face_t
       cairo_win32_font_face_t
    cairo_scaled_font_t
       cairo_ft_scaled_font_t
       cairo_win32_scaled_font_t

The methods on the subtypes are, however, not useful without bindings for fontconfig and FreeType or for the Win32 GDI, so most language bindings will choose not to bind these types.

The `cairo_font_face_set_user_data()`, and `cairo_font_face_get_user_data()` methods are provided for use in language bindings, and should not be directly exposed to applications.