Re: [Matplotlib-users] Best way to display image from URL in Python3

[Thomas C. <tca...@gm...>]

I think `six` (which we use to smooth over the 2/3 changes) has a way of
dealing with atleast the urllib renaming .

On Fri, Mar 20, 2015 at 11:58 AM Ryan Nelson <rne...@gm...> wrote:

> For me, if I change the script from the PR to what is shown below,
> everything works fine in both Python 2.7 and 3.4 (Anaconda environments,
> everything updated):
> ##################
> url = 'http://www.libpng.org/pub/png/img_png/pngnow.png'
> try:
>     import urllib2
>     data = urllib2.urlopen(url)
> except Exception:
>     import urllib.request
>     from io import BytesIO
>     data = BytesIO(urllib.request.urlopen(url).read())
>
> from matplotlib import pyplot
>
> image = pyplot.imread(data)  # crash on py3.x
> pyplot.imshow(image)
> pyplot.show()
> #################
> But as you can see, the Python 3 version requires the addition of BytesIO
> and read(). I take it that this is not supposed to be the case.
>
> Ryan
>
> On Fri, Mar 20, 2015 at 11:48 AM, Ryan Nelson <rne...@gm...>
> wrote:
>
>> Thanks, Ben. I should have made that more clear. If I run the code from
>> the PR, I get the following error:
>>
>> Traceback (most recent call last):
>>   File "junk.py", line 11, in <module>
>>     image = pyplot.imread(data)  # crash on py3.x
>>   File
>> "/home/nelson/apps/miniconda/lib/python3.4/site-packages/matplotlib/pyplot.py",
>> line 2215, in imread
>>     return _imread(*args, **kwargs)
>>   File
>> "/home/nelson/apps/miniconda/lib/python3.4/site-packages/matplotlib/image.py",
>> line 1270, in imread
>>     return handler(fname)
>> RuntimeError: _image_module::readpng: file not recognized as a PNG file
>>
>> My code that I'm trying to port essentially does the same thing, and I
>> get the same error. I ran this example just now from Anaconda Python 3.4
>> install with MPL 1.4.3.
>>
>> My impression from the PR was that this should work out of the box now. I
>> figured that maybe that was not quite the case. The implementations between
>> Py2 and 3 are quite different. Figured there must be a different way that I
>> wasn't aware of.
>>
>> Ryan
>>
>> On Fri, Mar 20, 2015 at 9:51 AM, Benjamin Root <ben...@ou...> wrote:
>>
>>> According to the PR you reference, the fix for this was merged back in
>>> Jan 2013, so that means that this fix is in version 1.2.x and up. Are you
>>> saying that you still can't do imread(urllib.request.urlopen(url))?
>>>
>>> On Thu, Mar 19, 2015 at 8:54 PM, Ryan Nelson <rne...@gm...>
>>> wrote:
>>>
>>>> Hello all,
>>>>
>>>> I'm porting over some code that used Py2.7 urllib2.urlopen(url) to grab
>>>> some image data from the net and load with pyplot.imread. It doesn't work
>>>> quite right in Py3.4. I found a couple of refs:
>>>>
>>>> https://github.com/matplotlib/matplotlib/pull/1650
>>>>
>>>> http://stackoverflow.com/questions/15183170/python-crash-when-downloading-image-as-numpy-array
>>>>
>>>> They suggest io.BytesIO(urllib.request.urlopen(url).read()) as a
>>>> replacement for Py3. Is this the best practice? Does anyone know a simpler
>>>> way to do this?
>>>>
>>>> Ryan
>>>>
>>>>
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>>
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