[reportlab-users] Patch for inclusion of CMYK images as CMYK, not converted to RGB

[Stevens, Ian]

Also, you'll want to remove the first call to image.convert('RGB') on
line 98.

Ian.


> -----Original Message-----

> From: reportlab-users-bounces at reportlab.com 

> [mailto:reportlab-users-bounces at reportlab.com] On Behalf Of 

> Stevens, Ian

> Sent: February 3, 2009 1:16 PM

> To: Support list for users of Reportlab software

> Subject: Re: [reportlab-users] Patch for inclusion of CMYK 

> images as CMYK,not converted to RGB

> 

> Thanks for including the patch. There's a typo, though:

> 

> ===================================================================

> --- src/reportlab/pdfgen/pdfimages.py   (revision 3416)

> +++ src/reportlab/pdfgen/pdfimages.py   (working copy)

> @@ -100,11 +100,11 @@

>          # Use the colorspace in the image

>          if image.mode == 'CMYK':

>              myimage = image

> -            colorspace = 'DeviceCMYK'

> +            colorSpace = 'DeviceCMYK'

>              bpp = 4

>          else:

>              myimage = image.convert('RGB')

> -            colorspace = 'RGB'

> +            colorSpace = 'RGB'

>              bpp = 3

>          imgwidth, imgheight = myimage.size

> 

> I've noticed the reverse color on JPEG images before but 

> since went with TIFF. I'll see what I can come up with.

> 

> Ian. 

> 

> > -----Original Message-----

> > From: reportlab-users-bounces at reportlab.com

> > [mailto:reportlab-users-bounces at reportlab.com] On Behalf Of Robin 

> > Becker

> > Sent: February 3, 2009 5:46 AM

> > To: Support list for users of Reportlab software

> > Subject: Re: [reportlab-users] Patch for inclusion of CMYK 

> images as 

> > CMYK, not converted to RGB

> > 

> > Stevens, Ian wrote:

> > > The following patch to pdfimage includes unconverted CMYK 

> images in 

> > > the PDF to preserve colours. We have clients who pass their PDFs 

> > > through a preflight tool before sending it to press and want all 

> > > content to be CMYK. The patch uses PIL's Image.mode to

> > decide whether

> > > to convert the image. We've been using this on our

> > production servers

> > > since 2.1 without problem.

> > >  

> > > Would it be possible to include this in the upcoming release? 

> > >

> > 

> > Yes, I see no obvious problem here. I think it's more 

> sensible to move 

> > the bpp setting into the first part of the patch though.

> > 

> > We should probably think more about greyscale and other 

> common image 

> > formats, but not today.

> > 

> > As for CMYK in general we have had patches in the past 

> related to CMYK 

> > in jpegs.

> > I notice in the code where we load a CMYK image from jpeg 

> that we set 

> > a decode array parameter which seems to reverse the sense of the 

> > colour values so instead of running 0-1 they run 1-0 

> instead. Anyone 

> > clever here know why we have to do that. I seem to remember when we 

> > started doing these patches that the tool (name

> > forgotten) which was creating the CMYK images required this 

> transform 

> > (otherwise all the colours were messed up).

> > 

> > > Thanks,

> > > Ian.

> > 

> > --

> > Robin Becker

> > _______________________________________________

> > reportlab-users mailing list

> > reportlab-users at reportlab.com

> > http://two.pairlist.net/mailman/listinfo/reportlab-users

> > 

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