fix: normalize F-Droid QR camera frames (#6319)

core/barcode/src/fdroid/kotlin/org/meshtastic/core/barcode/BarcodeAnalyzerFactory.kt

@@ -33,14 +33,14 @@ internal fun createBarcodeAnalyzer(onResult: (String) -> Unit): ImageAnalysis.An
 
     return ImageAnalysis.Analyzer { imageProxy ->
         try {
-            val buffer: ByteBuffer = imageProxy.planes[0].buffer
+            val lumaPlane = imageProxy.planes[0]
+            val buffer: ByteBuffer = lumaPlane.buffer.duplicate()
             val data = ByteArray(buffer.remaining())
             buffer.get(data)
 
             val width = imageProxy.width
             val height = imageProxy.height
-
-            val source = PlanarYUVLuminanceSource(data, width, height, 0, 0, width, height, false)
+            val source = PlanarYUVLuminanceSource(data, lumaPlane.rowStride, height, 0, 0, width, height, false)
             val binaryBitmap = BinaryBitmap(HybridBinarizer(source))
 
             val result = reader.decodeWithState(binaryBitmap)

core/barcode/src/testFdroid/kotlin/org/meshtastic/core/barcode/FdroidQrDecoderTest.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.core.barcode
+
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.BinaryBitmap
+import com.google.zxing.MultiFormatReader
+import com.google.zxing.PlanarYUVLuminanceSource
+import com.google.zxing.common.HybridBinarizer
+import com.google.zxing.qrcode.QRCodeWriter
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class FdroidQrDecoderTest {
+
+    @Test
+    fun `decodes Apple-compatible channel URL from padded camera plane`() {
+        val channelUrl = "https://meshtastic.org/e/#CgMSAQESBggBQANIAQ"
+        val dimension = 177
+        val matrix = QRCodeWriter().encode(channelUrl, BarcodeFormat.QR_CODE, dimension, dimension)
+        val packed =
+            ByteArray(dimension * dimension) { index ->
+                if (matrix[index % dimension, index / dimension]) 0 else 0xFF.toByte()
+            }
+        val rowStride = dimension + 11
+        val padded = ByteArray(rowStride * dimension) { 0x7F }
+        for (row in 0 until dimension) {
+            packed.copyInto(padded, row * rowStride, row * dimension, (row + 1) * dimension)
+        }
+
+        val decoded =
+            MultiFormatReader()
+                .decode(
+                    BinaryBitmap(
+                        HybridBinarizer(
+                            PlanarYUVLuminanceSource(padded, rowStride, dimension, 0, 0, dimension, dimension, false),
+                        ),
+                    ),
+                )
+
+        assertEquals(channelUrl, decoded.text)
+    }
+}