Constant Curiosity: September 2009

25 September 2009

The mighty PDF

PDF documents are a perfect export target in many applications because they're portable and look the same everywhere. So perfect in fact that there are virtual printers (like PDFCreator for Windows and integrated ones in Linux/*BSDs) which transform any printable file to a PDF.

But they are difficult when you want to change them or combine them.

I've had a folder sitting on my otherwise unburdened desktop for a year. It contained a bunch of scanned images which I wanted to aggregate into a nice and shiny single PDF file. Yeah. My google-fu had some slow reflexes this time and the first tries with FPDF, a PHP module, were unsuccessful. The images were in the correct format their manual demanded but I could only helplessly bang my head away as the scripts failed with errors of unsupported formats.

Sometimes my determination falters at moments like this and I put off trying to resolve the problem. But I had to push!

My google-fu got some well-deserved rest and found what I was looking for - a solution using GhostScript. By the way - this solution works for me on Ubuntu Linux but elsewhere YMMV.

Here's a script I ended up using (warning: It overwrites the original images.):

#!/bin/bash
for filename in *
do
    file -bi "$filename" | grep -q "image"
    if [ $? -eq 0 ]
    then
        echo "  Converting $filename"
        #Reduce image size by half 
        convert $filename -resize 50% $filename
        #Convert image to single-page PDF 
        convert $filename ${filename%.*}.pdf
    fi
done
gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=combined.pdf -dBATCH *.pdf

The bash script relies on ImageMagick (the convert command) and GhostScript (the gs command). Best thing is to copy it to a file in the folder with the images destined to comprise the PDF, marking the file as executable and running it! The final PDF will contain all the single-paged PDFs sorted in lexical order.

For the intricacies of GhostScript seen above I will let the devil speak for itself:

$ gs -h
GPL Ghostscript 8.64 (2009-02-03)
Copyright (C) 2009 Artifex Software, Inc.  All rights reserved.
Usage: gs [switches] [file1.ps file2.ps ...]
Most frequently used switches: (you can use # in place of =)
 -dNOPAUSE           no pause after page   | -q       `quiet', fewer messages
 -g<width>x<height>  page size in pixels   | -r<res>  pixels/inch resolution
 -sDEVICE=<devname>  select device         | -dBATCH  exit after last file
 -sOutputFile=<file> select output file: - for stdout, |command for pipe,
                                         embed %d or %ld for page #
Input formats: PostScript PostScriptLevel1 PostScriptLevel2 PostScriptLevel3 PDF

Vanity

Seeing my first post published was accompanied by a healthy dose of feeling accomplishment. But soon I found that the script code left something to be desired.

Prettiness!

After scouring the now humongous blogosphere I found people to relate to. But that's usually easy on the Internet. So after applying google-fu to the problem I found SyntaxHighlighter! Using it on Blogger requires a few simple steps which others have explained but I always try to do it my way so I learn something and memorize the process.

The gist of it is adding more javascript to your blog's HTML template. I appended my <head> section with this:

<link href='http://alexgorbatchev.com/pub/sh/current/styles/shCore.css' rel='stylesheet' type='text/css'/> 
<link href='http://alexgorbatchev.com/pub/sh/current/styles/shThemeDefault.css' rel='stylesheet' type='text/css'/> 
<script language='javascript' src='http://alexgorbatchev.com/pub/sh/current/scripts/shCore.js'></script> 
<script language='javascript' src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushBash.js'></script> 
<script language='javascript' src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushJava.js'></script> 
<script language='javascript' src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushPlain.js'></script> 
<script language='javascript' src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushXml.js'></script> 
<script type='text/javascript'> 
 SyntaxHighlighter.config.bloggerMode = true;
 SyntaxHighlighter.all();
</script>

The javascripts parse any <pre> blocks in your blog post and display the code in a nice way. The default style clashes a bit with my blog template but I might fix that. What good is dabbling in vanity if it doesn't achieve its purpose? :)

So let me try Hello World again:

#!/bin/bash
echo 'Hello, world!'
if [ $? -eq 0 ]
then
    ./comment > /dev/null
fi

23 September 2009

First post

Image by oskay via Flickr

Time for the first entry.

I could never come up with a good plan on what to write about or perhaps I just didn't want to write strictly about one subject. Oh how the times have changed.

Here I am, typing away precious moments trying to convey a message of what this blog will be about in an ambiguous natural language.

Let me give you a hint:

#!/bin/bash

echo 'Hello, world!'

if [ $? -eq 0 ]

then 

    ./comment

fi

Hopefully that didn't drive you away with WARP 9.9! :) Why don't you subscribe to the feed and be notified of changes automatically.

Constant Curiosity

25 September 2009

The mighty PDF

Vanity

23 September 2009

First post

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