Since the Nook A2 mode seems to be overridden when switching foreground activity, I've tried another approach with a background service which toggles A2 mode when requested by user. This way, the foreground activity isn't switched and "fast refreshing" mode works (until you change activity).
This fast refresh mode (called A2) is only possible because it uses only 1-bit depth, i.e, just black on white, meaning you can't see grayscale pictures but it's good enough for black text on white background and scrolling. I have not "created it", it is built-in from the device (you can test using the stock reader, it is activated when holding a page button). What I implemented is a way to activate and deactivate it at user will from inside any app.
Thanks to dairyknight for his N2EpdController class, which made this possible.
Thanks to bardo8430 for bringing the idea.
Thanks to AndroSS source code for screenshots used in automatic contrast.
01/Mar: Now when you launch the app and it is already running, it will activate NoRefresh mode. So you can also use an activation shortcut to the app using NookTouchTools (i.e. B&N's book icon at top left corner).
02/Mar: Improve activation shortcut to perform toggle between modes. Tap gestures aren't needed anymore (use "-noGestures" apk version if you don't want them).
04/Mar: Got rid of initial ghosting by redrawing the screen after activating A2.
04/Mar (2): Minor improvement of removing ghosting at screen edges.
12/Mar (Beta): Now you can adjust contrast in A2 mode. Images shouldn't be dark or black anymore if you raise the contrast a bit.
22/May: Completely redesigned version 2.0:
- Several options can be customized via settings screen.
- NoRefresh can be toggled by manual app shortcut, tap gestures or automatically according to screen animation (new).
- New App Whitelist to avoid unwanted activation in specific apps (except for manual mode).
- Background service can be launched at boot.
- Small improvements and tweaks.
- Custom app icon (finally
06/Jun: Fix crash on empty whitelist
08/Jul: (Version 2.1)
- Automatic contrast when activating NoRefresh, according to total "brightness" of the screen (simple algorithm). This should ask you for root permission.
- Also supports manual setting in specific situations (customizable).
- Fix possible crash at startup.
26/Jul: (Version 2.2)
- Fix contrast setting behaviour
- Alternative version with fixed compatibility for FW 1.2.0 available at https://github.com/marspeople/NoRefreshToggle/downloads
First Video: http://youtu.be/6pBPsyno5PY
Other Video: http://youtu.be/kBbl6egyPsQ
Another demo: http://youtu.be/5b7JjllImjM