PIL PNG IOError

[Ryan, Adam]

Howard & Sean,

Thanks for the input.  I'm using Howard's mapscript build and indeed turning
interlace off did solve the problem.

So, for PIL and PNG, I have added this to my pdf output script:

ofO = mapO.outputformat
ofO.setOption("INTERLACE","OFF")

Thanks for your continued help with my python endeavors.  Cheers,

Adam


> -----Original Message-----
> From: Howard Butler [mailto:hobu at IASTATE.EDU]
> Sent: Wednesday, March 30, 2005 7:43 AM
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] PIL PNG IOError
>
>
> 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
>