[Image-SIG] show() bug in Image.py of PIL 1.1 (maybe)

[Man-Yong Lee]

Hi, Image-SIG guys

I'm new to this sig.

I think there is a bug in show()ing Image object via ``xv''
in case there's no support of Tkinter.

My environment is like this:
    Red Hat Linux 6.2
    Python 1.52
    PIL 1.1

Around the line 975 of Image.py:

def _showxv(self, title=None, command=None):

    if os.name == "nt":
        format = "BMP"
        if not command:
            command = "start"
    else:
        format = None
        if not command:
            command = "xv"
            if title:
                command = command + " -name \"%s\"" % title

Following the codes above, the value of format is always None
when os.name is not "nt"

    base = getmodebase(self.mode)
    if base != self.mode and self.mode != "1":
        file = self.convert(base)._dump(format=format)
    else:
        file = self._dump(format=format)

So, self._dump(format=format) will be called as
self._dump(format=None).

This makes these codes raise TypeError exception! (around the
line 312)

    def _dump(self, file=None, format="PPM"):
        import tempfile
        if not file:
            file = tempfile.mktemp()
        self.load()
        if format == "PPM":
            self.im.save_ppm(file)
        else:
            file = file + "." + format
            ^^^^^^^^^^^^^^^^^^^^^^^^^^
            self.save(file, format)
        return file

Because format is always None, ``file = file + "." + format''
raise TypeError exception. (string type + None!)

My dirty hack is like this:

Before calling file = self._dump(format=format), I inserts
these lines.

        if not format:                          # FIXME
            format = self.format
        if not format:
            format = 'PPM'
        file = self._dump(format=format)

Thanks for reading this.

Am I wrong?  I want your comment.

__
Bryan Lee			Linux Korea, Inc.