Each version of Android improves the tools that developers have at their disposal, and that certainly includes visual tools. Starting with version N and the Pixel Launcher, Google seems to be increasingly pushing circular icons. One of the new features in Android O, available in its first Developer Preview today, is the ability to automatically change the shape of any given icon with the new adaptive icon toolset.

Developers now have the option to alter an icon's border with shaped masks, including the more-or-less default rounded square, different sizes of circles, and a "squircle" shape. These icons can be used in any portion of the user interface, but obviously they're meant to be used primarily on the homescreen (Pixel Launcher or otherwise). The idea is that an OEM like Samsung or HTC will provide a unifying mask, which will allow developers to integrate almost any existing app icon into the broader user interface with minimal effort, and no extra graphics work on the icon itself.

Different layers can be used for more effective backgrounds and "floating" icons. Android O will automatically add such animations as are needed to the masked icons, like outlines, zooms, "bounces," and drop shadows. The icons will be visible in shortcuts, the settings menu, the default Share dialog, and the overview screen.

As with all Developer Preview features, Google may add or remove functions to the new Adaptive Icons tools between now and the release of Android O later this year.

Source: Android Developers