The elementary Human Interface Guidelines have recently been updated to include some newer widgets available to developers in the latest versions of Granite and found in the upcoming elementary OS Luna.
We've added popovers to the HIG. From the HIG entry:
Popovers are like a contextual dialog. They display transient content directly related to something that was clicked on and close when clicked out of, like menus.
You can see popovers in use with Slingshot, the indicators, in Midori, in Maya, and in other apps designed for elementary OS. Check out the popover HIG entry.
The source list is a relatively new addition to Granite, so we added it to the HIG. We've actually been using this style all the way back since the first elementary apps, but now it's standardized and in both Granite and the HIG. From the HIG entry:
A source list may be used as a high-level form of navigation sidebar. Source lists are useful for showing different locations, bookmarks, or categories within your app.
Source lists are used in apps like Noise, Files, third-party apps designed for elementary OS, and hopefully soon in Geary. Check out the source list HIG entry.
Decorated windows are also a somewhat new addition to Granite, so they've been added to the HIG. They work very nicely with Gala and are helping us establish a standardized way of tackling client-side decorations. From the HIG entry:
A decorated window is used to present the user with a simple, focused, non-resizable, and stylish dialog.
Decorated windows are already being used in apps like Files, Maya, Noise, and technically every Granite app as the About dialog. Check out the decorated window HIG entry.
This last update isn't actually a widget like the others; it's a workflow guideline. We decided to specify how apps should handle background tasks according to the elementary philosophies. From the HIG entry:
In general, an app's back- and front-ends should be separated, allowing for background processing of tasks.
The entry goes on to specify how apps should behave if performing one-time background tasks, when performing tasks after the window is closed, and more. Check out the background tasks HIG entry for more details.
We're working hard to keep the Human Interface Guidelines up-to-date and helpful. The next major push for the HIG is going to be linking each widget's page with the API for the widget in Granite to make it easier for devs to learn how to implement it. In addition, we'll be working on making sure all other widgets are in the HIG with clear use cases. Lastly, we're pushing to include more visual examples for devs to better understand the exact meaning and significance of the guidelines.