[Image-SIG] Re: [Tutor] Converting to PDF

["Héctor Villafuerte D."]

Hi all!
Danny was so right! This is a bug in PIL.
I changed '/DctDecode' and '/DCTDecode' in PdfImagePlugin.py
and it worked just fine!
Thanks Danny and all you Python people.
Hector


Danny Yoo wrote:

>
>On Wed, 7 Jan 2004, [ISO-8859-1] "H?ctor Villafuerte D." wrote:
>
>
>>Hi all,
>>I'm trying to generate PDFs with this little script:
>>
>>-----SCRIPT-------------------------
>>import fileinput, os, Image
>>
>>def get_calls(dir, file):
>>    im = Image.open(dir + file)
>>    im.save(dir + '_' + file, 'PDF')
>>
>>if __name__ == '__main__':
>>    dir = 'c:\\tmp\\scan\\'
>>    for x in os.listdir(dir):
>>        if x.split('.')[1] == 'jpg':
>>            print x
>>            get_calls(dir, x)
>>
>
>
>Hi Hector,
>
>
>I looked into the PdfImagePlugin.py source from version 1.1.4 of the
>Python Imaging Library,
>
>    http://www.pythonware.com/products/pil/
>
>
>And you appear to have run into a bug in PIL!  The code in question in
>PIL/PdfImagePlugin.py is:
>
>###
>    if filter == "/ASCIIHexDecode":
>        ImageFile._save(im, op, [("hex", (0,0)+im.size, 0, None)])
>    elif filter == "/DCTDecode":
>        ImageFile._save(im, op, [("jpeg", (0,0)+im.size, 0, im.mode)])
>    elif filter == "/FlateDecode":
>        ImageFile._save(im, op, [("zip", (0,0)+im.size, 0, im.mode)])
>    elif filter == "/RunLengthDecode":
>        ImageFile._save(im, op, [("packbits", (0,0)+im.size, 0, im.mode)])
>    else:
>        raise ValueError, "unsupported PDF filter"
>###
>
>
>That block is within the _safe() function in PdfImagePlugin.py.  But
>there's only one block of code that assigns to this 'filter' variable:
>
>###
>    if im.mode == "1":
>        filter = "/ASCIIHexDecode"
>        config = "/DeviceGray", "/ImageB", 1
>    elif im.mode == "L":
>        filter = "/DctDecode"
>        # params = "<< /Predictor 15 /Columns %d >>" % (width-2)
>        config = "/DeviceGray", "/ImageB", 8
>    elif im.mode == "P":
>        filter = "/ASCIIHexDecode"
>        config = "/Indexed", "/ImageI", 8
>    elif im.mode == "RGB":
>        filter = "/DCTDecode"
>        config = "/DeviceRGB", "/ImageC", 8
>    elif im.mode == "CMYK":
>        filter = "/DCTDecode"
>        config = "/DeviceRGB", "/ImageC", 8
>    else:
>        raise ValueError, "illegal mode"
>###
>
>
>'filter' here has three possible values:
>
>    ['/ASCIIHexDecode',
>     '/DctDecode',
>     '/DCTDecode']
>
>
>Notice the case difference here between '/DctDecode' and '/DCTDecode'.
>Python is case sensitive.  This is a bad sign.  *grin*
>
>
>The block that we're running into problems with, the one that throws the
>exception, checks for:
>
>    ["/ASCIIHexDecode",
>     "/DCTDecode",
>     "/FlateDecode",
>     "/RunLengthDecode"]
>
>
>It doesn't handle "/DctDecode"!  Furthermore, there's no way 'filter' can
>be '/RunLengthDecode', so there's some dead code here too.
>
>There's definitely a bug here.  Send a holler out to the Python Imaging
>Library folks.  *grin*
>
>    http://mail.python.org/mailman/listinfo/image-sig
>
>and get them to fix it so no one else runs into this.
>
>
>
>In the meantime, my best guess right now to fix the bug is to modify
>PdfImagePlugin.py and switch over the '/DctDecode' string to '/DCTDecode'
>and see if that clears up the problem.  Unfortunately, I can't test this
>hypothesis without a sample JPEG image.
>
>
>
>
>
>By the way: you may want use os.path.join() to join together the directory
>name with the file name.  The code in get_calls():
>
>
>>def get_calls(dir, file):
>>    im = Image.open(dir + file)
>>    im.save(dir + '_' + file, 'PDF')
>>
>
>may not get the correct name of the directory, since the path separator
>might be missing.
>
>I can see that you have hardcoded the path separator embedded in the 'dir'
>directory name within your main program, but if you are using get_calls()
>from another program, then there's no guarantee that the directory name
>ends with the path separator character.
>
>
>
>Hope this helps!
>
>
>
>