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urs mantel
Joined: 02 Nov 2010
Posts: 16
Location: Switzerland
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 Posted: Mon May 16, 2016 10:04 pm Post subject: PIL image processing error |
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Hello Jean-François,
I recently upgraded from 2.5.4 to 2.7.9
since then processing of JPEG images with PIL is not possible
>>>import PIL, PIL.Image
>>>filename = '1.jpg'
>>>im = PIL.Image.open(filename)
>>>print im.format
JPEG
>>>im.load()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/python_root/local/PIL/ImageFile.py", line 207, in load
raise IOError(error + " when reading image file")
IOError: decoding error when reading image file
with 2.5.4 (May 14 2011) it was ok (with corresponding LIB)
2.7.6, 2.7.9, 2.7.11 are not ok
any hints?
Thanks
Urs |
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jfp
Joined: 12 Jul 2004
Posts: 636
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| Posted: Wed May 18, 2016 6:30 am Post subject: |
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Hello Urs,
be sure that the file has a record format Fixed length or stream lf.
There are some change in Python around thiis, in don't remember exactly in which version.
JF |
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urs mantel
Joined: 02 Nov 2010
Posts: 16
Location: Switzerland
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| Posted: Wed May 18, 2016 10:44 pm Post subject: |
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Hello Jean-François,
excellent remote diagnose !
If the file has RFM:STMLF instead of STM then it will be processed by PIL.
Nevertheless - strange enough the whole processing is made in python
HTML form with input type=file (JPEG) is submitted through WASD PYRTE Python to the script
| Code: |
form = cgi.FieldStorage()
fileitem = form["PHOTOFILE"]
...
fout = file(temp_filename, 'wb')
while 1:
chunk = fileitem.file.read(100000)
if not chunk: break
fout.write (chunk)
fout.close()
if format != "JPEG":
do something
im = Image.open(temp_filename)
im.thumbnail(size,mode) <---- raises exeption
im.save(temp_filename_thumbnail)
...
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Even hundreds of already processed files have RFM:STMLF automatically received from Python (2.5.4) – why not with 2.7.9/11?
Where should I or could I say save as STMLF ?
Urs |
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jfp
Joined: 12 Jul 2004
Posts: 636
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| Posted: Thu May 19, 2016 3:36 pm Post subject: |
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Hello Urs,
The only reason, I can imagine, to have a file with RFM:STM instead of RFM:STMLF is that there is a previous version of the file with the incorrect RFM format.
Python, as it is written in C, always create file using RFM:STMLF.
But if a previous version exist, OpenLMS CRTL create a new version with the same RFM as the previous version.
To be sure to create a correct file format, you can use the file class directly which allow to specified rmsattr instead if the open function.
| Code: | $ python -c help(file)
Help on class file in module __builtin__:
class file(object)
| file(name[, mode[, buffering[, rmsattr]]]) -> file object
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| Open a file. The mode can be 'r', 'w' or 'a' for reading (default),
| writing or appending. The file will be created if it doesn't exist
| when opened for writing or appending; it will be truncated when
| opened for writing. Add a 'b' to the mode for binary files.
| Add a '+' to the mode to allow simultaneous reading and writing.
| If the buffering argument is given, 0 means unbuffered, 1 means line
| buffered, and larger numbers specify the buffer size. The preferred way
| to open a file is with the builtin open() function.
| Add a 'U' to mode to open the file for input with universal newline
| support. Any line ending in the input file will be seen as a '\n'
| in Python. Also, a file so opened gains the attribute 'newlines';
| the value for this attribute is one of None (no newline read yet),
| '\r', '\n', '\r\n' or a tuple containing all the newline types seen.
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| 'U' cannot be combined with 'w' or '+' mode.
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| Under OpenVMS you can specify an optional list or tuple of RMS attributes:
| >>> rmsattr = ['ctx=stm','rfm=fix','mrs=512']
| >>> fp = file('XYZ.DAT','w',0,rmsattr)
| See the C RTL manual for a full list of attributes. If rmsattr is not
| specified, or has a value of None, then default attributes will be applied.
| A value of "" forces no attributes.
...
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JF |
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urs mantel
Joined: 02 Nov 2010
Posts: 16
Location: Switzerland
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| Posted: Sun May 22, 2016 9:18 pm Post subject: |
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Hello Jean-François,
everything is ok with the saved files from HTML form - all files are with RAT:STMLF
(I've got an old file as example with RAT:STM (must have been saved with FTP or Pathworks))
The uploaded files get RAT:STMLF automatically
However, I'm still not able to process the files with PIL.
Are you able to open and load a JPEG file?
| Code: |
>>>import PIL.Image
>>>im = PIL.Image.open('filename.jpg')
>>>im.load()
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Thanks
Urs |
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jfp
Joined: 12 Jul 2004
Posts: 636
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| Posted: Mon May 23, 2016 5:32 pm Post subject: |
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Hello Urs,
Using 2.7.11 I reproduce the problem, seem a GIF file open and load correctly but a JPEG one fail.
May be time to upgrade PIL to latest version...
Or better, as it seem that PIL is dead, to switch to Pillow: https://github.com/python-pillow/Pillow
JF |
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jfp
Joined: 12 Jul 2004
Posts: 636
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| Posted: Thu Nov 17, 2016 11:39 am Post subject: |
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Hello Urs,
I have, probably, found the bug.
It is a regression in the port of libjpeg.
This is fixed, and be provided with Python 2.7.12
JF |
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