</p>
<pre class="programlisting">
cairo_surface_t *
cairo_image_surface_create_from_png (const char	*filename);

cairo_surface_t *
cairo_image_surface_create_from_png_stream (cairo_read_func_t read_func,
					    void             *closure);

cairo_status_t
cairo_surface_write_to_png (cairo_surface_t	*surface,
			    const char		*filename);

cairo_status_t
cairo_surface_write_to_png_stream (cairo_surface_t	*surface,
				   cairo_write_func_t	write_func,
				   void			*closure);</pre>
<p>
      The expectatio