Fix QR processing resolution and allow front camera use for device linking.

qr/lib/src/main/java/org/signal/qr/QrProcessor.kt

@@ -67,7 +67,7 @@ class QrProcessor {
 
   companion object {
     private val TAG = Log.tag(QrProcessor::class.java)
-
+    /** For debugging only */
     var listener: ((LuminanceSource) -> Unit)? = null
   }
 }

qr/lib/src/main/java/org/signal/qr/QrScannerView.kt

@@ -57,6 +57,11 @@ class QrScannerView @JvmOverloads constructor(
     })
   }
 
+  fun toggleCamera() {
+    Log.d(TAG, "Toggling camera")
+    scannerView?.toggleCamera()
+  }
+
   companion object {
     private val TAG = Log.tag(QrScannerView::class.java)
   }

qr/lib/src/main/java/org/signal/qr/ScannerView.kt

@@ -7,4 +7,5 @@ import androidx.lifecycle.LifecycleOwner
  */
 interface ScannerView {
   fun start(lifecycleOwner: LifecycleOwner)
+  fun toggleCamera()
 }

qr/lib/src/main/java/org/signal/qr/ScannerView19.kt

@@ -18,8 +18,27 @@ internal class ScannerView19 constructor(
   private val scanListener: ScanListener
 ) : FrameLayout(context), ScannerView {
 
+  private var lifecycleOwner: LifecycleOwner? = null
   private var scanningThread: ScanningThread? = null
-  private val cameraView: QrCameraView
+  private lateinit var cameraView: QrCameraView
+
+  private val lifecycleObserver = object : DefaultLifecycleObserver {
+    override fun onResume(owner: LifecycleOwner) {
+      val scanningThread = ScanningThread()
+      scanningThread.setScanListener(scanListener)
+      cameraView.onResume()
+      cameraView.setPreviewCallback(scanningThread)
+      scanningThread.start()
+
+      this@ScannerView19.scanningThread = scanningThread
+    }
+
+    override fun onPause(owner: LifecycleOwner) {
+      cameraView.onPause()
+      scanningThread?.stopScanning()
+      scanningThread = null
+    }
+  }
 
   init {
     cameraView = QrCameraView(context)
@@ -28,22 +47,16 @@ internal class ScannerView19 constructor(
   }
 
   override fun start(lifecycleOwner: LifecycleOwner) {
-    lifecycleOwner.lifecycle.addObserver(object : DefaultLifecycleObserver {
-      override fun onResume(owner: LifecycleOwner) {
-        val scanningThread = ScanningThread()
-        scanningThread.setScanListener(scanListener)
-        cameraView.onResume()
-        cameraView.setPreviewCallback(scanningThread)
-        scanningThread.start()
+    this.lifecycleOwner?.lifecycle?.removeObserver(lifecycleObserver)
+    this.lifecycleOwner = lifecycleOwner
+    lifecycleOwner.lifecycle.addObserver(lifecycleObserver)
+  }
 
-        this@ScannerView19.scanningThread = scanningThread
-      }
-
-      override fun onPause(owner: LifecycleOwner) {
-        cameraView.onPause()
-        scanningThread?.stopScanning()
-        scanningThread = null
-      }
-    })
+  override fun toggleCamera() {
+    cameraView.toggleCamera()
+    lifecycleOwner?.let {
+      lifecycleObserver.onPause(it)
+      lifecycleObserver.onResume(it)
+    }
   }
 }

qr/lib/src/main/java/org/signal/qr/ScannerView21.kt

@@ -2,9 +2,9 @@ package org.signal.qr
 
 import android.annotation.SuppressLint
 import android.content.Context
+import android.util.Size
 import android.widget.FrameLayout
 import androidx.annotation.RequiresApi
-import androidx.camera.core.AspectRatio
 import androidx.camera.core.Camera
 import androidx.camera.core.CameraSelector
 import androidx.camera.core.ImageAnalysis
@@ -28,19 +28,42 @@ internal class ScannerView21 constructor(
   private val listener: ScanListener
 ) : FrameLayout(context), ScannerView {
 
+  private var lifecyleOwner: LifecycleOwner? = null
   private val analyzerExecutor = Executors.newSingleThreadExecutor()
   private var cameraProvider: ProcessCameraProvider? = null
+  private var cameraSelector: CameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
   private var camera: Camera? = null
   private var previewView: PreviewView
   private val qrProcessor = QrProcessor()
 
+  private val lifecycleObserver: DefaultLifecycleObserver = object : DefaultLifecycleObserver {
+    override fun onDestroy(owner: LifecycleOwner) {
+      cameraProvider = null
+      camera = null
+      analyzerExecutor.shutdown()
+    }
+  }
+
   init {
     previewView = PreviewView(context)
     previewView.layoutParams = LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)
     addView(previewView)
   }
 
+  override fun toggleCamera() {
+    cameraSelector = if (cameraSelector == CameraSelector.DEFAULT_BACK_CAMERA) {
+      CameraSelector.DEFAULT_FRONT_CAMERA
+    } else {
+      CameraSelector.DEFAULT_BACK_CAMERA
+    }
+
+    lifecyleOwner?.let { start(it) }
+  }
+
   override fun start(lifecycleOwner: LifecycleOwner) {
+    this.lifecyleOwner?.lifecycle?.removeObserver(lifecycleObserver)
+    this.lifecyleOwner = lifecycleOwner
+
     previewView.post {
       Log.i(TAG, "Starting")
       ProcessCameraProvider.getInstance(context).apply {
@@ -54,13 +77,7 @@ internal class ScannerView21 constructor(
       }
     }
 
-    lifecycleOwner.lifecycle.addObserver(object : DefaultLifecycleObserver {
-      override fun onDestroy(owner: LifecycleOwner) {
-        cameraProvider = null
-        camera = null
-        analyzerExecutor.shutdown()
-      }
-    })
+    lifecycleOwner.lifecycle.addObserver(lifecycleObserver)
   }
 
   private fun onCameraProvider(lifecycle: LifecycleOwner, cameraProvider: ProcessCameraProvider?) {
@@ -71,10 +88,14 @@ internal class ScannerView21 constructor(
 
     Log.i(TAG, "Initializing use cases")
 
-    val preview = Preview.Builder().build()
+    val resolution = Size(480, 640)
+
+    val preview = Preview.Builder()
+      .setTargetResolution(resolution)
+      .build()
 
     val imageAnalysis = ImageAnalysis.Builder()
-      .setTargetAspectRatio(AspectRatio.RATIO_4_3)
+      .setTargetResolution(resolution)
       .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
       .build()
 
@@ -88,10 +109,13 @@ internal class ScannerView21 constructor(
     }
 
     cameraProvider.unbindAll()
-    camera = cameraProvider.bindToLifecycle(lifecycle, CameraSelector.DEFAULT_BACK_CAMERA, preview, imageAnalysis)
+    camera = cameraProvider.bindToLifecycle(lifecycle, cameraSelector, preview, imageAnalysis)
 
     preview.setSurfaceProvider(previewView.surfaceProvider)
 
+    Log.d(TAG, "Preview:  ${preview.resolutionInfo}")
+    Log.d(TAG, "Analysis: ${imageAnalysis.resolutionInfo}")
+
     this.cameraProvider = cameraProvider
   }
 

qr/lib/src/main/java/org/signal/qr/kitkat/QrCameraView.java

@@ -47,7 +47,7 @@ public class QrCameraView extends ViewGroup {
   private final OnOrientationChange onOrientationChange;
 
   private volatile Optional<Camera> camera             = Optional.empty();
-  private final    int              cameraId           = CameraInfo.CAMERA_FACING_BACK;
+  private volatile int              cameraId           = CameraInfo.CAMERA_FACING_BACK;
   private volatile int              displayOrientation = -1;
 
   private @NonNull  State                    state             = State.PAUSED;
@@ -161,6 +161,14 @@ public class QrCameraView extends ViewGroup {
     return state != State.PAUSED;
   }
 
+  public void toggleCamera() {
+    if (cameraId == CameraInfo.CAMERA_FACING_BACK) {
+      cameraId = CameraInfo.CAMERA_FACING_FRONT;
+    } else {
+      cameraId = CameraInfo.CAMERA_FACING_BACK;
+    }
+  }
+
   @SuppressWarnings("SuspiciousNameCombination")
   @Override
   protected void onLayout(boolean changed, int l, int t, int r, int b) {