The default Pixel Launcher of Android O supports five distinct shapes of app icons, users running the latest developer preview of Google's upcoming operating system have uncovered. While the round icon shape is used by default, the Pixel Launcher also supports several options for customizing the look of system app icons on the Home and App Drawer screens, including "Squircle," "Rounded corner rect," "Square," and "Cylinder." The newly added menu that's available as of the second developer preview of Android O contains a "Change icon shape" option on the main Settings screen that's located near the bottom of the interface, immediately above the "About" section. Tapping that option prompts a pop-up window from which users are able to choose their preferred app icon shape. The changes made using this menu are seemingly system-wide, with the exception of the Dock icons that aren't modifiable using this method and stay round regardless of one's system settings.
The feature is a part of Google's recently announced adaptive icons and developers will have to modify their icons in order for their apps to be compatible with the newly uncovered functionality of Android O. While the latest major build of the company's operating system is still in an experimental phase and some features may be scrapped by the time it's released, the ability to change the shape of one's app icons likely won't be one of them due to the amount of focus Google already put on adaptive icons and the way in which they enhance the overall user experience of Android. Refer to the gallery below to see how various app icons look in practice.
As Google isn't expecting that all developers who ever released an Android app that's still available for download will be able to update their software with support for adaptive icons for a number of reasons, the new feature won't break the icons of incompatible apps. Those will instead always be set to default while the others will change according to one's system settings. Even though this design decision may result in an inconsistent user experience depending on the user's choice of apps, it's a tradeoff between completely breaking the icons incompatible apps and trying to pressure all developers into updating them, something that cannot be achieved realistically.