Rendering differences
Because Android apps run in a window under Chrome OS, there are small differences in how apps are rendered on Chromebooks. These differences are outlined below.
Tasks, windows, and transparency
A taskconsists of a stack of activities that the user interacts with when running an app. Tasks are presented on Chrome OS as a window with a title bar, with the apps layered on top of each other. Each activity can then be partially translucent, allowing the lower layers to show through.
In a conventional Android app, the previous task or the desktop shows through beneath the task. In this way there is always something visible beneath a translucent task.
This does not work in a window environment for the following reasons:
- The visible content below a window cannot be controlled and could therefore be anything.
- All fully transparent pixels would “magically” swallow all touch/mouse events.
- Window elements might visually be disconnected from the caption and confuse the user with possibly unconnected visual elements.
To mitigate this problem, Play for Chrome OS draws a semi-transparent rectangle behind each window. For this reason, apps can never be 100% transparent when running under Chrome OS, even when using the Theme.Translucent.NoTitleBar theme.
Recommended
Optimizing display size
Explains how to determine display resolution for rendering.
TopHatch unveils Concepts' immersive canvas on Chrome OS and Android
By optimizing for Chrome OS, Concepts was able to unlock a large and growing user base while increasing the average time users spend in their app.
GDC 2019 recap: Optimizing Android games for larger screens & foldables
A recap of Google at the Game Developer Conference 2019 with some helpful coding tips and tricks.