Last time, I gave a demo of a Mallard document rendered in a way that adapts to handheld devices like phones. Because Mallard is not a presentational language, most of the formatting can be adjusted automatically, and authors don’t have to worry about anything. But sometimes, you really do want to change the content when viewing on a handheld device.

First, though, let’s look at some specific formatting differences between desktop and mobile. For each of the pages below, click the ‘Desktop’ and ‘Mobile’ links above the iframe to see the difference.

  • Desktop Help – The purely decorative hover previews are turned off for mobile. (Good luck hovering with your finger anyway.) Also, the three-column grid changes to a two-column grid.
  • Delete files and folders – The notes and step lists use all the available horizontal space. The automatic links at the bottom fill the whole page width as well.
  • Sound, video & pictures – The two-column link layout changes to a single column, and the link boxes span the entire page width, making them easier to tap.

But sometimes we add content that’s visually helpful on large screens, but cumbersome at small sizes. Things like screenshots are often nice to have, as long as they don’t get in the way. This is where conditional processing comes into play. I’ve been busy retooling Mallard conditional processing to allow things like this:

<media src="figures/shell-top-bar.png" if:test="!target:mobile"/>

The result is an image that’s only displayed in non-mobile reading environments. Switch between desktop and mobile on these pages to see it in action:

This isn’t limited to images, of course. You can use conditional processing on any block element or list item. What’s more, Mallard conditional processing allows full branching and fallback, giving you an easy way to display one thing for the desktop, and something else for mobile.