Hi everyone

I use Inkscape to build up designed pages, adding text boxes, shapes and images from GIMP. Then export that to PDF to further process in Acrobat, combine all Inkscape pages into a single PDF for example.
The images are from GIMP XCF files that I copy and paste into Inkscape, they appear to be embedded as PNG data when viewing the XML source using the XML Editor. And I understand that the PDF export in Inkscape leaves the images completely as is and just embeds them into the PDF container... this is a good thing!

Inkscape PDF export is brilliant for me as it produces full resolution PDFs that exactly match the design in Inkscape. When exporting to PS/EPS then converting to PDF with Acrobat/Distiller I've found text boxes and images sometimes get chopped around with weird artefacts appearing.

When I try and open a PDF with embedded PNG images in Acrobat and use the PDF Optimizer function to downsample the images to say 72dpi, the Acrobat PDF Optimizer doesn't touch the images and the file size stays the same.
So thinking this was a problem with Acrobat and its processing of PNG images, I created a PDF using a PNG and the PDF Optimizer worked fine. I took some advice from the Adobe forums and it seems that the PDF that Cairo (the export engine that Inkscape uses) creates the PDF in such a way that might be stopping the Acrobat PDF Optimizer from being able to process the images.

Here's a quote from the Adobe forums...

The PDF creation software (cairo?) has certainly done something odd. It has wrapped up the image in a tiling pattern, then painted the pattern just once. PDF shrinking software isn't likely to mess with the contents of patterns, they are normally tiny special effect bitmaps not to be adjusted... maybe there's an option to change this on creation.

Here's a link to a sample PDF that has been generated from Inkscape... http://www.thenetzone.co.uk/fail/acrobatpngtest.pdf

So my questions:
Has anyone encountered this before and found a way around it, to get the Acrobat PDF Optimizer (or Reduce File Size) functions to run on PDFs created by Inkscape/Cairo?
Are there any options in Cairo (that are not exposed by Inkscape) that can perhaps change the way Cairo embeds the images in the PDF?

I realise this is an Inkscape forum and my questions are relating to Acrobat and the Cairo engine within Inkscape but I thought I would post to see if anyone has encountered anything similar.

Cheers, B

Aha! Apparently this is solved in a later release of Cairo, 1.8.8 is from 2009 and is quite old.
I was using Inkscape 0.48.1 on Windows.

I found a newer version of Inkscape hiding away on SourceForge (0.48.3.1-2) which includes Cairo 1.11.2 (23/01/2011)
And the PDFs generated with that are successfully processed by the PDF Optimizer in Acrobat.

Hope this helps someone out!

Cheers, B