Extracting embedded images from SVG

With Inkscape, one can open and edit PDF files. But when the PDF comes with embedded images, the resulting SVG keeps the images as an embedded base64 encoded data. I wanted to extract those embedded images from the resulting SVG. But I didn't want to use the "export bitmap" option on Inkscape to extract those images, as within this way I wouldn't really know the original resolution besides the fact that Inkscape would re-encode the image data. So I wrote this one line to extract all images from one SVG.

i=1; grep data:image test.svg | cut -d "," -f 2 | cut -d \" -f 1 |while read line ; do echo $line | base64 --decode > $i.png ; i=$((i+1)); done

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More trickery with gnuplot dumb terminal

In my post " Plotting memory usage on console " the chart doesn't pan the data. Now, using a named pipe, the effect got a little bit nicer. First, we have to run the memUsage.sh script to get a file filled with memory usage info: ./memUsage.sh > memUsage.dat & Then we have to create a named pipe: mkfifo pipe Now we have to run another process to tail only the last 64 lines from the memUsage.dat while [ 1 ]; do tail -64 memUsage.dat> pipe; done & And now we just have to plot the data from the pipe: watch -n 1 'gnuplot -e "set terminal dumb;p \"pipe\" with lines"' And that is it!

Replace transparency in PNG images with white background (for lots of files...)

I had to remove transparency from a PNG image file from the command line... and stack overflow came into my help[1]... But I needed it for lots of files... then, adding a "while read line" did the job: ls -1 *.png | cut -d . -f 1 | while read line; do convert -flatten $line.png flatten/$line.png ; done; [1] Replace transparency in PNG images with white background https://stackoverflow.com/questions/2322750/replace-transparency-in-png-images-with-white-background

Pettry rendered LaTeX equations using PHP

When I was writing a simple scientific webapp, during my undergrads studies, I needed to generate some equations to be shown by the app. I was already familiar with LaTeX equation formatting syntax, so I decided to use this nice peace of software. So, after "googling" a little, I found the imgtex , written by Koji Nakamaru , which is a fast CGI script, written in perl. What I did, was port it to PHP. To run it, you must have a LaTeX distribution and the dvipng software both installed on the same machine which you will run the PHP script. Here is the PHP code: To use this code, you just have to pass the LaTeX commands through GET to the PHP. For example, adding the following string to your URL: http://localhost/imgtex.php?res=300&cmd=x=\frac{-b\pm\sqrt{-4ac}}{2a} The res variable sets the resolution for the generated image and the cmd specifies the LaTeX command. This way, the above URL will produce the following image:

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