Plotting with AJAX + Javascript

A friend of mine had written an application which communicates with a small microcotroled board and saves data read from this board on a mysql database. He wants to plot these data on the web. He wrote a PHP script using the GD lib. He did a real good job, but he wants it to plot the data dynamically and an http refresh made things a little ugly. He is now trying to plot directly with AJAX + Javascript. He is trying to use Flot, which is a javascrit for plotting data.
Another usefull resource for realtime web graphics is the CavasDemos.

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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!

powerpoint slides to jpeg

Looking for some way to convert power point slides to JPG, I've found this site: http://www.commandlinefu.com/commands/browse It has tons of good linux command line tips. And here is the tip about the pdf to jpg which brought me there: http://www.commandlinefu.com/commands/view/719/convert-pdf-to-jpg And to convert the powerpoint to pdf before, one can issue the unoconv command: unoconv -f pdf slides.ppt

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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