This is similar to Spark [1], except Spark uses standard Unicode characters whereas Histogrem requires a custom font. Still, it's nice that Histogrem offers greater precision.
I did a similar thing (with Bill Zeller and John Udell) as a ubiquity/twitter extension a couple of years earlier[1]... but in practice the low resolution of the standard unicode caracters makes them just a novelty; the technique's been reinvented several times but hasn't found a niche.
Even this font doesn't quite hack it for me - the curves are too wide to take in the time series at a glance.
Another easy way to put histograms in a text file is to make them sideways. Below is one for the sum of three dice rolls. Python code + larger example: http://codepad.org/YmkQDvni .
You are bound to viewing the document in a browser. This may not be a problem in most cases, but console users cannot see them.
There is also a large overhead in the amount of code that needs to be written to position and scale everything. For example, what if I wanted to add another line?
Finally, because it's text, it's easy to move around. To build the site, I just copied some text out of some of the files I already had and stuck it where it needed to go. How would I have done it if it was a canvas element?
Interesting question. You could do something like this: http://jsfiddle.net/AwynM/4/ and keep the values as values for people who use curl, and replace them dynamically using JS
Did someone edit the title? I swear it used to contain the full project/tagline.
My one complaint is that this really does not work "right inside a text file," atleast as far as "inside a text file" is usually interpreted. When I saw the project tagline I was really excited and somewhat skeptic. When I see "do x in a text file" i think of a text file I can send to someone and not require that they use a certain font. But, I do realize given that constraint it's a lot harder to implement a histogram. Neat project though...
Typeface.js/cufon/etc were very useful for a while. It's easy to switch to @font-face now: upload your font here http://www.fontsquirrel.com/fontface/generator, it will give you some CSS rules, just use the font name in your styles like `font-family: Histogrem;`.
What you see in your browser is not the actual font. It was first transformed by typeface.js so that people without the font installed could still see what it looks like in their browsers.
Some people have mentioned (seemingly great) alternatives to displaying uninstalled fonts, but I haven't had a chance to try them out.
If you were to view text with the actual font, it would have no problems scaling.
[1] https://github.com/holman/spark