PIL PNG IOError

[Howard Butler]

Adam,

Try turning off interlacing in your OUTPUTFORMAT.  I've had PIL choke on
interlaced PNGs before (depending on the PIL version).

Howard

At 09:41 AM 3/30/2005, Sean Gillies wrote:
>On Mar 29, 2005, at 3:58 PM, Adam Ryan wrote:
>
> > Hello to all,
> >
> > I'm using Python Mapscript, ReportLab and PIL to generate PDF files on
> > Windows XP.  I generate an image using mapscript, save it, and then
> > insert
> > it into my pdf 'canvas':
> >
> > Canvas.drawInlineImage(myfile,x,y,w,h)
> >
> > If my mapfile outputformat is gif, no problem - I get a nice pdf file.
> >  But
> > if my outputformat is png, I get an IOError:
> >
> > File "C:\python23\lib\site-packages\PIL\ImageFile.py", line 192, in
> > load
> > IOError: unknown error when reading image file
> >
> > Your thinking I'm posting to the wrong listserv right?  Well, if I take
> > that png file and open it up in Micro$oft Paint and then save it, my
> > routine then works without a problem.  So I compared the two png files
> > (before and after saving with Paint) with gdalinfo but got identical
> > results.  I did notice that there was a file size decrease after
> > saving.
> > But I don't know what else could be different about the files.  Any
> > ideas?
> >
> > Here are two examples of file size reduction with output format:
> >
> > OUTPUTFORMAT
> >   NAME png
> >   DRIVER "GD/PNG"
> >   MIMETYPE "image/png"
> >   IMAGEMODE PC256
> >   EXTENSION "png"
> > END
> >
> > Reduction: 146kb to 137kb
> >
> > outputformat
> >   name "png"
> >   driver "GD/PNG"
> >   imagemode "RGB"
> >   mimetype "image/png"
> >   extension "png"
> > End
> >
> > Reduction: 272kb to 205kb
> >
> > Any sugestions would be grand.  Cheers to all,
> >
> > Adam
> >
> >
>
>Adam,
>
>Sorry, but I cannot reproduce this problem on Linux or on windows
>(Python 2.3.3 and PIL 1.1.5).  PIL opens my mapscript PNG output just
>fine.
>
>Can you remind me of the source of your MapServer/mapscript software?
>
>Sean
>
>
>--
>Sean Gillies
>sgillies at frii dot com
>http://users.frii.com/sgillies