I have a Samsung Galaxy Tab 4 (SM-T235) tablet running Android version 4.4.2. It is 7 inch, which is nice, but sometimes (for example, when walking) I would like to be able to hold my device in one hand and only use my thumb to interact with the app that I am using. Perhaps even change the resolution so that is like a regular mobile device.
Basically I would like to have a way to run apps in a smaller resolution and have it not scaled to fit the display so that I can reach everything with my thumb using only one hand.
See the image below for an example that i have in mind.
I have complete root access and am a developer (I don't really need 'simplified' answers, give me the tech details!)