Simple pie charts with fallback, today

Five years ago, I had written this extensive Smashing Magazine article detailing multiple different methods for creating simple pie charts, either with clever use of transforms and pseudo-elements, or with SVG stroke-dasharray. In the end, I mentioned creating pie charts with conic gradients, as a future technique. It was actually a writeup of my “The Missing Slice” talk, and an excerpt of my CSS Secrets book, which had just been published.

I was reminded of this article today by someone on Twitter:

I suggested conic gradients, since they are now supported in >87% of users’ browsers, but he needed to support IE11. He suggested using my polyfill from back then, but this is not a very good idea today.

Indeed, unless you really need to display conic gradients, even I would not recommend using the polyfill on a production facing site. It requires -prefix-free, which re-fetches (albeit from cache) your entire CSS and sticks it in a <style> element, with no sourcemaps since those were not a thing back when -prefix-free was written. If you’re already using -prefix-free, the polyfill is great, but if not, it’s way too heavy a dependency.

Pie charts with fallback (modern browsers)

Instead, what I would recommend is graceful degradation, i.e. to use the same color stops, but in a linear gradient.


Use MathML today, with CSS fallback!

These days, I’m working on the slides for my next talk, “The humble border-radius”. It will be about how much work is put into CSS features that superficially look as simple as border-radius, as well as what advances are in store for it in CSS Backgrounds & Borders 4 (of which I’m an editor). It will be fantastic and you should come, but this post is not about my talk.

As you may know, my slides are made with HTML, CSS & JavaScript. At some point, I wanted to insert an equation to show how border-top-left-radius (as an example) shrinks proportionally when the sum of radii on the top side exceeds the width of the element. I don’t like LaTeX because it produces bitmap images that don’t scale and is inaccessible. The obvious open standard to use was MathML, and it can even be directly embedded in HTML5 without all the XML cruft, just like SVG. I had never written MathML before, but after a bit of reading and poking around existing samples, I managed to write the following MathML code: