Display viewport only at the right bottom of the screen I have a Geniatech ATV1220 android set top box running android 4.2.2 and am using an arduino with motion sensor connected to it to modify content on a website when someone is in front of the sensor via NodeJS. 

This works great, but what I would like to do is to manipulte the complete system viewport of the android system. For example if someone steps in front of the sensor, the whole system should be displayed in a reduced size like 1/4 original at the bottom right side of the screen while the other area should just display black or basically nothing.

It is really hard to find something because of the pretty common keywords like display, viewport, size and so on. I could probably do it dependent on individual applications but I also want to use it in third party applications, which I cannot modify.

Currently I am sometimes using commands like this:

echo 1 &gt;/sys/class/graphics/fb0/blank


to modify the actual content that is displayed, in this case it all turns black/blank and I wonder if there is a similar way to achieve what I want to do. Any help is greatly appreciated.
What worked in the end was using the Xposed Framework and installing "One-handed mode" like explained here: How to get a one-handed mode on almost any rooted Android device.