new_contents: import cairo
  
  # this shows that even though we are using integer values
  # for set_source_surface, the subpixel translation is
  # capturing pixel values from adjacent pixels of the source
  
  src = cairo.ImageSurface(cairo.FORMAT_RGB24, 60, 40)
  cr = cairo.Context(src)
  
  #cr.set_source_rgb(1, 0, 0)
  #cr.rectangle(0, 0, 20, 40)
  #cr.fill()
  cr.set_source_rgb(0, 1, 0)
  cr.rectangle(20, 0, 20, 40)
  cr.fill()
  #cr.set_source_rgb(0, 0, 1)
  #cr.rectangle(40, 0, 20, 40)
  #cr.fill()
  src.write_to_png("src.png")
  
  
  dst = cairo.ImageSurface(cairo.FORMAT_ARGB32, 400, 400)
  cr = cairo.Context(dst)
  cr.set_source_rgb(1, 1, 1)
  cr.paint()
  
  for z in range(0, 400):
      cr.translate(0.01, 1)
      cr.set_source_surface(src, -20, 0)
      cr.rectangle(0, 0, 20, 40)
      cr.fill()
  dst.write_to_png("dst.png")
  
subject: Add script to show what cairo is doing that is strange