8e3169e49b
271 attempts at 720x1280 with no detection means either downsampling
killed the finder patterns or drawImage is silently painting blank
pixels (a known iOS WebKit failure mode for some video-stream sources).
- Drop the 600px scaling cap. Feed the full native video frame to
jsQR. Per-frame cost goes up but is still fine; the win is jsQR
sees finder patterns at full sharpness.
- Add a one-time sanity check that walks the first ImageData buffer
looking for a non-zero pixel. If everything is 0,0,0 the canvas is
blank (drawImage failed) and we surface that as 'px:BLANK' in the
status line — telling us instantly to switch decoder strategies
rather than chasing tuning.
- Status line now also shows the last jsQR call outcome:
r:found / r:no_code / r:empty / r:error: ...
So we can confirm whether jsQR is even being invoked successfully.
Status format compacted to fit one line on phone:
jsqr · f1234 a567 720x1280 rs4 px:ok r:no_code
Version: shopfloor 19.0.20 -> 19.0.21.