ai-server prints the QR as block characters, which take the terminal's
foreground colour. On a dark-themed terminal that comes out as a
photographic negative, and ZXing looks only for a dark code on a light
ground, so the in-app scanner silently never matched it -- while the
phone's own camera app, which tries both, did.
Fixing it in the scanner rather than by having the server force its
colours means however the code gets displayed stops mattering: a light
terminal, a dark one, a screenshot someone inverted, a printout.
MIXED_SCAN alternates normal and inverted frames, so the cost is half the
frame rate at each polarity. Checked against the library's own
MixedDecoder off-device: the plain decoder reads the normal image and
returns nothing for the inverted one, and the mixed decoder reads both
within two frames.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QQz6R4kBQcWSHBNZMgBnjL
irisandClaude Opus 5
0522123a33