CompactSeedQR format

[kdmukai]

Adds a new CompactSeedQR format which encodes the QR data as bytes in order to fit into a smaller QR code size.

A 24-word seed is encoded as its 256-bit entropy into a 25x25 QR code.
A 12-word seed is encoded as its 128-bit entropy into a 21x21 QR code.

A mnemonic's checksum word is uniquely determined by the full entropy and so it is trivially calculated from this data in order to rebuild the full seed (in other words: it's implicit already in the data and so doesn't need to be stored explicitly).

CHANGES:

• Requires zbar 0.23 or higher
• Requires forked update of pyzbar
• Updates qrcode for more advanced rendering options (CircleModuleDrawer)
• Adds option screen to select "Standard" SeedQR or the new "Compact" format.
• Reads the new CompactSeedQR format for 12- or 24-word seeds while maintaining full reverse-compatibility with the "Standard" SeedQR format.
• Alters QR decoding pipeline to keep data in binary format
• Renders the zoomed-in SeedQR with dots instead of filled squares
• Updated SeedQR template using dot targets instead of the mini grid lines.
• Begins a safer approach to check for a settings.ini field before trying to read it in Settings.__config_to_data but a better overall approach to setting and storing config is probably in order.

Misc:

• Somewhat ugly workaround to reset the Singleton classes as needed in the test suite.
• Controller can now be instantiated with disable_hardware so that the test suite can keep re-instantiating the Controller without creating gpio conflicts on the hardware itself.

TODO:

• Binary download option for zbar?
• Settings option to enable CompactSeedQR; hide and use standard SeedQR by default
• Verify that pyzbar/zbar are fine scanning everything with binary=True.
• Support 12- or 24-word entry for 25x25 SeedQR template generator
• Documentation for both SeedQR formats
• Review test suite
• Add test cases

[newtonick]

@kdmukai can you add "compact_seedqr_enabled = False" to the settings var in tests/test_controller.py

When I ran the test suite it failed because it was expecting compact_seedqr_enabled when performing configparser in the settings class.

--- a/tests/test_controller.py
+++ b/tests/test_controller.py
@@ -33,6 +33,7 @@ def test_singleton_get_instance_preserves_state():
         software = Prompt
         qr_density = 2
         custom_derivation = m/0/0
+        compact_seedqr_enabled = False
     """
     config = configparser.ConfigParser()
     config.read_string(settings)

[kdmukai]

@newtonick ah, dang. I must have made my test suite changes before that Settings change happened. Good catch!

This opened a bit of a can of worms on the testing side that prompted some good improvements.

• Adding the above to the test suite does fix the test suite, but would be an unresolved bug for any actual users with existing settings.ini files! Added check for the new field and to handle its absence gracefully.
• The additional test to confirm this behavior introduced a new problem: Re-initializing each Singleton class. pytest cannot isolate them across tests so we have to use a somewhat ugly way to reset them each time.
• Reseting the Controller means re-mapping(?) the buttons. The second attempt throws a RuntimeError: "Conflicting edge detection already enabled for this GPIO channel". So that required a new disable_hardware on the Controller config.

[newtonick]

LGTM. Great work here!

[SeedSigner]

Appreciate this Keith and thank you for the review Nick!