On Tue, 01 Mar 2016 09:56:56 +0100, Peter Otten wrote:
> Wildman via Python-list wrote:
>
>> I want to take an image file, convert it to XBM format and
>> display it. Thanks to Mr. Otten I can open and display the
>> XBM image without any problems. The script first calls an
>> external program for the image conversion then I can open
>> and display it. Of course, I am left with the XBM file that
>> needs to be deleted. It seemed to me to be a better approach
>> to use stdout and pipe thereby eliminating the XBM file
>> altogether. Here is code I have so far but I'm not sure
>> what to do next...
>>
>> convert = "convert " + fileName + " -resize 48x48! -threshold 55% xbm:-"
>> p = subprocess.Popen([convert], stdout=subprocess.PIPE, shell=True)
>> xbmFile, err = p.communicate()
>
> Why would you need a shell?
I guess it is a Linux thing. If I don't use it, I get
the below error. A shell window does not actually open.
I presume it runs in the background while executing the
subprocess command.
Exception in Tkinter callback
Traceback (most recent call last):
File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1535, in __call__
return self.func(*args)
File "./test.py", line 59, in open_image
p = subprocess.Popen(command, stdout=subprocess.PIPE)
File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1335, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
>> The variable fileName contains the image file path and name.
>> The variable convert contains the complete command. The last
>> argument in the command tells the convert utility to covert
>> to an XBM and to direct the output to stdout. After the above
>> code runs xbmFile contains the actual image, which is plain
>> text. (X BitMap (XBM) is a plain text binary image format.)
>>
>> My question is how do I take the xbmFile variable and convert
>> it to an image object that can be displayed? The technique
>> for displaying an image from a file does not work or at least
>> I have not been able to get it to work.
>
> I think Image.open() accepts a file-like object, so
>
> import io
> ...
> command = [
> "convert", fileName,
> "-resize", "48x48!",
> "-threshold", "55%",
> "xbm:-"]
> p = subprocess.Popen(command, stdout=subprocess.PIPE)
> xbmFile, err = p.communicate()
> openImage = Image.open(io.BytesIO(xbmFile))
>
> should work.
I does work, perfectly. During my research I didn't run across
anything about using io. The learning process continues...
I am in your debt again. Thank you.
--
<Wildman> GNU/Linux user #557453
"Be at war with your vices, at peace with your neighbors,
and let every new year find you a better man."
-Benjamin Franklin
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