Gets the target surface for the cairo context as passed to
cairo_create().
This function will always return a valid pointer, but the result
can be a "nil" surface if cr is already in an error state,
(ie. cairo_status() != CAIRO_STATUS_SUCCESS).
A nil surface is indicated by cairo_surface_status()
!= CAIRO_STATUS_SUCCESS.
Since 1.0
Gets the target surface for the cairo context as passed to cairo_create(). This function will always return a valid pointer, but the result can be a "nil" surface if cr is already in an error state, (ie. cairo_status() != CAIRO_STATUS_SUCCESS). A nil surface is indicated by cairo_surface_status() != CAIRO_STATUS_SUCCESS. Since 1.0