[cairo] CAIROMM: surfaces

[Jonathon Jongsma]

[I hope this is the right list for cairomm discussion -- there doesn't
seem to be a separate list for language bindings.]

I noticed that in the "Creating a language binding for cairo" section
of the cairo manual, it's recommended that the cairo_surface_t type be
implemented as a heirarchy of types.  In the current cairomm code,
there's only a single Surface class that basically just wraps an image
surface.  I've been playing around with adding more types of surfaces
to cairomm and I've currently got the following arrangement:

Surface (base class -- apps should use one of the derived types)
  - ImageSurface
  - PdfSurface
  - PsSurface
  - GlitzSurface
  - Win32Surface
  - XlibSurface
  - SvgSurface
  - Other surfaces: BEOS, Quartz, etc.

Does anyone have problems with this, or opinions on how this should be
implemented in the C++ bindings?