Sunday, May 24, 2009

inkscape, pdf and posters

SICSA asked everyone to make a big poster to make their opening do more academic (here's the result). This was the first time I'd used inkscape to produce an A0 pdf, and there were some hiccups due to the large number of vector illustrations I included [edit - some glitch with scribd, click zoom out to view] -



The first time I exported to pdf, all the non-screen grab figures were vector line art. This gave a nice 3Mb PDF file that would take a massive 3 minutes to open, and without Inkscape's nice blurs. This wasn't really good enough. I decided to turn those diagrams into bitmaps to render nicely. The Glasgow guidelines for creation of PDF posters (as well as specifiying sensible font sizes) says that 300 dpi is the target printing resolution - so this is what I should target in my conversions.

[edit] the rest of this post is for an old version of inkscape. Newer versions export blurs to pdf automatically (save copy as..., select .pdf, in dialogue box "rasterise filter effects" is selected automatically), and you can set the "Create Bitmap Copy" resolution in file -> inkscape preferences -> bitmaps -> resolution for Create Bitmap Copy.

The default image res was 90 dpi, not enough for printing. To set inkscape's default conversion dpi to 300 - I followed instructions here & then restarted inkscape-

The resolution or size of the created bitmaps can be set in preferences.xml (no GUI yet). In , specifying minsize= gives the minimum size of the generated bitmap in pixels (regardless of the object size), while resolution= sets the constant resolution (different pixel size for different object sizes).

Then it was a case of selecting all figures in the document and using Edit->Make bitmap copy. Because of the bounds of the outlines in inkscape doesn't include blurs, sometimes it was necessary to add a large white background rectangle before creating the bitmap copy. Once the copy is made, the original vector art can be deleted.

There were a couple of bugs were the converted figures had a small transparent border that rendered grey in Adobe's PDF reader, but this was remedied by editing the bitmap copies in the gimp and painting out the border, the re-opening the inkscape document.

After this the Save As... -> pdf -> OK worked like a charm. The result was 8Mb, but loaded much quicker and with less glitches.


sicsa logo

The PDF included the above image in vector form - it was created from a 3D model that was imported into blender (from my prototype code). The poster was made on a bit of a deadline and rendering out this geometry nicely would have taken too long. Thankfully the render-to-svg script for blender worked like a charm and created vector art from the blender scene. Then a nice blur was added from the input geometry.

Here's another poster I made in inkscape - waaay better than some of the powerpoint mush you get out there! The inkscape file is here (23Mb, don't open in browser, use inkscape!).

city sculpt - ict pioneers poster

Finally, if you've got lots of graphics getting the poster to print can be a little difficut - our department has a HP DesignJet (500 plus) connected to an old print server. I've wasted a ton of ink on buffer-underflows trying to print over the network - and "out of memory - data lost" errors, leaving big missing portions of the poster (white rectangles). The solution was to spool from a laptop connected straight to the printer. Here're the settings I used to print a landscape poster sideways:

designjet (settings for landscape poster)

5 comments:

  1. Nice poster

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  2. Thanks Jes - still the same stuff that I've been studying since my Master's tho!

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  3. Hi, any chance I could get the Inkscape svg source for the posters to poke at?

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    1. ping, see comment below!

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  4. I've updated the page with a link to download the best poster as a svg.
    (http://www.dcs.gla.ac.uk/~tkelly/bits/epsrc_pioneers_poster.svg)

    I'm not certain it was the final cut, but it looks pretty close. The file has lots of embedded images, and expects certain fonts that you might have to search on the internet for!

    Happy drawing, let me know what you use it for!

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