=== THIS PROJECT IS ABANDONED ===
Android 8 disallows any app to draw over notification panel or navigation buttons, so Pixel Filter cannot work properly on any newer phone, and nothing can be done about that.
Current bugs:
Add Poisson-disc sampling algorithm for lulz.
Option to start on battery percentage.
Fix crashes when watching light level and rotating the phone.
Diagonal lines on some devices - auto-calibrate bitmap offset using a screenshot.
Filter does not cover navigation buttons fully when the keyboard is shown.