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

[Stevens, Ian]

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

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