The resolution changer works using a hidden Android API called IWindowManager. Originally, Google restricted access to this API starting with Android Pie, however, it allowed developers to disable the API blacklist by modifying the secure settings.
Resolution Changer first unlocks the blacklisted APIs, and then applies the required resolution and screen density.
If you don't specify a height or width, Resolution Changer will simply use the resolution currently set by the device.
If you don't specify a density, Resolution Changer attempts to calculate the appropriate density based on the diagonal size of the device's screen.
WARNING:
If you specify a broken resolution and are unable to fix it, follow these steps:
1. Connect device to PC
2. Open CMD or Terminal (depending on OS)
3. Type these commands:
adb shell wm size reset
adb shell wm density reset
