read.func function.cairoImageSurfaceCreateFromPngStream(con)CairoSurface] a new CairoSurface initialized with the contents
of the PNG file or a "nil" surface if the data read is not a valid PNG image
or memory could not be allocated for the operation. A nil
surface can be checked for with cairo_surface_status(surface) which
may return one of the following values:CAIRO_STATUS_NO_MEMORY
CAIRO_STATUS_READ_ERROR
Alternatively, you can allow errors to propagate through the drawing
operations and check the status on the context upon completion
using cairoStatus.