Earlier today, Google released Android 11 Developer Preview 3 for Pixel devices. I installed the latest build onto my Pixel 3a XL and have been documenting what I've found so far (a more detailed article is soon to come!) One of the more interesting new features we discovered in this release is the ability to resize picture-in-picture windows. This feature is currently in testing and is not enabled by default, however.

Google introduced picture-in-picture windows to Android smartphones in Android 8.0 Oreo. You can open a video in a picture-in-picture window in supported applications by pressing the home button or performing the home gesture when the video is playing. By default, the PiP window floats on top of the screen in the bottom right-hand corner, but the user can move the PiP window around or dismiss it by dragging it to the bottom of the screen.

In Android 11 DP2, Google added code for resizing PiP windows under the PipResizeGestureHandler class in SystemUI, but the feature was not yet functional. In Android 11 DP3, though, the ability to resize picture-in-picture windows is now fully functional after manually issuing a development command. PiP windows can be resized by touching right outside one of the four corners and then dragging outward or inward to expand or shrink the window, respectively. The aspect ratio of the window will be maintained when resizing so as to not distort the video. Here's a demonstration of the new feature on my Pixel 3a XL running Android 11 DP3:

As you can see in the screen recording above, I launched a YouTube video into a PiP window and then enlarged the window by dragging outward near the corners. Placing your finger on the exact area where you need to initiate the resize gesture is a bit tricky, but I managed to resize the window twice in the video. We don't know if Google plans on releasing this feature in the stable Android 11 release, but we'll keep an eye out on it for further developments.