png2svg.py

import sys
import cairo

src_file, out_file = sys.argv[1:3]

src = cairo.ImageSurface.create_from_png(src_file)
svg = cairo.SVGSurface(out_file, src.get_width(), src.get_height())
ctx = cairo.Context(svg)
ctx.set_source_surface(src)
ctx.paint()