Tags: tufte

2

sparkline

The typography of a web book

I’m a sucker for classic old-style serif typefaces: Caslon, Baskerville, Bembo, Garamond …I love ‘em. That’s probably why I’ve always found the typesetting in Edward Tufte’s books so appealing—he always uses a combination of Bembo for body copy and Gill Sans for headings.

Earlier this year I stumbled on a screen version of Bembo used for Tufte’s digital releases called ET Book. Best of all, it’s open source:

ET Book is a Bembo-like font for the computer designed by Dmitry Krasny, Bonnie Scranton, and Edward Tufte. It is free and open-source.

When I was styling Resilient Web Design, I knew that the choice of typeface would be one of the most important decisions I would make. Remembering that open source ET Book font, I plugged it in to see how it looked. I liked what I saw. I found it particularly appealing when it’s full black on full white at a nice big size (with lower contrast or sizes, it starts to get a bit fuzzy).

I love, love, love the old-style numerals of ET Book. But I was disappointed to see that ligatures didn’t seem to be coming through (even when I had enabled them in CSS). I mentioned this to Rich and of course he couldn’t resist doing a bit of typographic sleuthing. It turns out that the ligature glyphs are there in the source files but the files needed a little tweaking to enable them. Because the files are open source, Rich was able to tweak away to his heart’s content. I then took the tweaked open type files and ran them through Font Squirrel to generate WOFF and WOFF2 files. I’ve put them on Github.

For this book, I decided that the measure would be the priority. I settled on a measure of around 55 to 60 characters—about 10 or 11 words per line. I used a max-width of 27em combined with Mike’s brilliant fluid type technique to maintain a consistent measure.

It looks great on small-screen devices and tablets. On large screens, the font size starts to get really, really big. Personally, I like that. Lots of other people like it too. But some people really don’t like it. I should probably add a font-resizing widget for those who find the font size too shocking on luxuriously large screens. In the meantime, their only recourse is to fork the CSS to make their own version of the book with more familiar font sizes.

The visceral reaction a few people have expressed to the font size reminds me of the flak Jeffrey received when he redesigned his personal site a few years back:

Many people who’ve visited this site since the redesign have commented on the big type. It’s hard to miss. After all, words are practically the only feature I haven’t removed. Some of the people say they love it. Others are undecided. Many are still processing. A few say they hate it and suggest I’ve lost my mind.

I wonder how the people who complained then are feeling now, a few years on, in a world with Medium in it? Jeffrey’s redesign doesn’t look so extreme any more.

Resilient Web Design will be on the web for a very, very, very long time. I’m curious to see if its type size will still look shockingly large in years to come.

Canvas sparklines

I like sparklines a lot. Tufte describes a sparkline as:

…a small intense, simple, word-sized graphic with typographic resolution.

Four years ago, I added sparklines to Huffduffer using Google’s chart API. That API comes in two flavours: a JavaScript API for client-side creation of graphs, and image charts for server-side rendering of charts as PNGs.

The image API is really useful: there’s no reliance on JavaScript, it works in every browser capable of displaying images, and it’s really flexible and customisable. Therefore it is, of course, being deprecated.

The death warrant for Google image charts sets the execution date for 2015. Time to start looking for an alternative.

I couldn’t find a direct equivalent to the functionality that Google provides i.e. generating the images dynamically on the server. There are, however, plenty of client-side alternatives, many of them using canvas.

Most of the implementations I found were a little heavy-handed for my taste: they either required jQuery or Processing or both. I just wanted a quick little script for generating sparklines from a dataset of numbers. So I wrote my own.

I’ve put my code up on Github as Canvas Sparkline.

Here’s the JavaScript. You create a canvas element with the dimensions you want for the sparkline, then pass the ID of that element (along with your dataset) into the sparkline function:

sparkline ('canvasID', [12, 18, 13, 12, 11, 15, 17, 20, 15, 12, 8, 7, 9, 11], true);

(that final Boolean value at the end just indicates whether you want a red dot at the end of the sparkline).

The script takes care of normalising the values, so it doesn’t matter how many numbers are in the dataset or whether the range of the numbers is in the tens, hundreds, thousands, or hundreds of thousands.

There’s plenty of room for improvement:

  • The colour of the sparkline is hardcoded (50% transparent black) but it could be passed in as a value.
  • All the values should probably be passed in as an array of options rather than individual parameters.

Feel free to fork, adapt, and improve.

The sparklines are working quite nicely, but I can’t help but feel that this isn’t the right tool for the job. Ideally, I’d like to keep using a server-side solution like Google’s image charts. But if I am going to use a client-side solution, I’m not sure that canvas is the right element. This should really be SVG: canvas is great for dynamic images and animations that need to update quite quickly, but sparklines are generally pretty static. If anyone fancies making a lightweight SVG solution for sparklines, that would be lovely.

In the meantime, you can see Canvas Sparkline in action on the member profiles at The Session, like here, here, here, or here.

Update: Ask and thou shalt receive. Check out this fantastic lightweight SVG solution from Stuart—bloody brilliant!