Error when canvas is blank

[fikr4n]

I got this when running image2term.py from examples.

Traceback (most recent call last):
  File "image2term.py", line 107, in <module>
    __main__()
  File "image2term.py", line 102, in __main__
    args['output'].write(image2term(args['image'], args['threshold'], args['ratio']))
  File "image2term.py", line 66, in image2term
    return can.frame()
  File "/tmp/drawille/examples/drawille.py", line 403, in frame
    return self.line_ending.join(self.rows())
  File "/tmp/drawille/examples/drawille.py", line 354, in rows
    minrow = min(self.pixels.keys())
ValueError: min() arg is an empty sequence

I tried to inspect and conclude that it was because the (default) threshold causes the image become blank. I also tried to do a simple run by creating a Canvas() and call frame(). The result was the same, so that I conclude that a blank canvas leads to an error.

[asciimoo]

Thanks, fixed ( 8df28b2 )