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Greptile Summary

Fixes QR code scanning on devices where the camera Y plane row stride differs from the image width (e.g., Xperia 10 V on LineageOS). The core change passes plane.rowStride instead of imageProxy.width as the dataWidth parameter to ZXing's PlanarYUVLuminanceSource, preventing row misalignment that corrupted image data and blocked QR detection.

• Row stride fix: Uses plane.rowStride as dataWidth in PlanarYUVLuminanceSource to correctly handle devices with alignment padding bytes in the Y plane buffer. This is the correct approach — dataWidth represents the byte stride between rows, not the logical image width.
• TRY_HARDER hint: Adds DecodeHintType.TRY_HARDER to the ZXing reader hints for improved QR detection reliability at the cost of slightly more CPU per frame.
• consumeWindowInsets removal: Removes .consumeWindowInsets(paddingValues) so that .navigationBarsPadding() on the bottom instruction card is not suppressed, fixing layout on devices with 3-button navigation.

Confidence Score: 4/5

• This PR is safe to merge — it fixes a real device-specific QR scanning bug with a well-understood approach.
• The row stride fix is the standard correct approach for handling Y plane padding in Android camera frames with ZXing. The TRY_HARDER hint is a safe additive change. The consumeWindowInsets removal is intentional and correctly motivated for the QR scanner's specific layout (Scaffold with only a topBar, where child content needs its own navigation bar padding). Score is 4 rather than 5 because the buffer size vs. dataWidth*dataHeight validation in PlanarYUVLuminanceSource could theoretically throw on devices where the last row lacks padding, though in practice Android camera buffers are sized to avoid this.
• No files require special attention — the single changed file contains a well-documented, targeted fix.

Important Files Changed

Sequence Diagram

sequenceDiagram
    participant Camera as CameraX
    participant Analyzer as QrCodeAnalyzer
    participant ZXing as ZXing MultiFormatReader
    participant UI as QrScannerScreen

    Camera->>Analyzer: analyze(imageProxy)
    Analyzer->>Analyzer: Check scan cooldown
    Analyzer->>Analyzer: Get Y plane buffer
    Note over Analyzer: data = ByteArray(buffer.remaining())
    Analyzer->>Analyzer: Get plane.rowStride
    Note over Analyzer: rowStride may include<br/>padding bytes > width
    Analyzer->>ZXing: PlanarYUVLuminanceSource(data, rowStride, height, 0, 0, width, height, false)
    Note over ZXing: dataWidth = rowStride ensures<br/>correct row byte offsets
    ZXing->>ZXing: HybridBinarizer → BinaryBitmap
    ZXing->>ZXing: decode(bitmap) with TRY_HARDER
    alt QR code found
        ZXing-->>Analyzer: Result with text
        Analyzer->>UI: onQrCodeDetected(qrText)
    else No QR code
        ZXing-->>Analyzer: Exception (ignored)
    end
    Analyzer->>Analyzer: imageProxy.close()

_{Last reviewed commit: 208ae0f}