Android Translate Showcase: Update to use CameraX Beta and PreviewView

android/translate-showcase/app/build.gradle

@@ -61,9 +61,11 @@ dependencies {
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
 
     // Add CameraX dependencies
-    def camerax_version = "1.0.0-alpha05"
+    def camerax_version = "1.0.0-beta05"
     implementation "androidx.camera:camera-core:${camerax_version}"
     implementation "androidx.camera:camera-camera2:${camerax_version}"
+    implementation "androidx.camera:camera-lifecycle:$camerax_version"
+    implementation "androidx.camera:camera-view:1.0.0-alpha12"
 
     // Add ML Kit dependencies
     implementation 'com.google.android.gms:play-services-mlkit-text-recognition:16.0.0'

android/translate-showcase/app/src/main/java/com/google/mlkit/showcase/translate/analyzer/TextAnalyzer.kt

@@ -25,52 +25,71 @@ import androidx.camera.core.ImageAnalysis
 import androidx.camera.core.ImageProxy
 import androidx.lifecycle.MutableLiveData
 import com.google.android.gms.tasks.Task
-import com.google.android.gms.tasks.Tasks
 import com.google.mlkit.common.MlKitException
 import com.google.mlkit.showcase.translate.util.ImageUtils
 import com.google.mlkit.vision.common.InputImage
 import com.google.mlkit.vision.text.Text
 import com.google.mlkit.vision.text.TextRecognition
 import java.lang.Exception
 
-
 /**
  * Analyzes the frames passed in from the camera and returns any detected text within the requested
  * crop region.
  */
 class TextAnalyzer(
     private val context: Context,
     private val result: MutableLiveData<String>,
-    val widthCropPercent: Int,
-    val heightCropPercent: Int
+    private val imageCropPercentages: MutableLiveData<Pair<Int, Int>>
 ) : ImageAnalysis.Analyzer {
     private val detector = TextRecognition.getClient()
 
-    // Flag to skip analyzing new available frames until previous analysis has finished.
-    private var isBusy = false
-
-    override fun analyze(imageProxy: ImageProxy, imageRotationDegrees: Int) {
+    @androidx.camera.core.ExperimentalGetImage
+    override fun analyze(imageProxy: ImageProxy) {
         val mediaImage = imageProxy.image ?: return
-        if (isBusy) return
 
-        isBusy = true
+        val rotationDegrees = imageProxy.imageInfo.rotationDegrees
+
+        // We requested a setTargetAspectRatio, but it's not guaranteed that's what the camera
+        // stack is able to support, so we calculate the actual ratio from the first frame to
+        // know how to appropriately crop the image we want to analyze.
+        val imageHeight = mediaImage.height
+        val imageWidth = mediaImage.width
+
+        val actualAspectRatio = imageWidth / imageHeight
+
         val convertImageToBitmap = ImageUtils.convertYuv420888ImageToBitmap(mediaImage)
-        val cropRect = Rect(0, 0, mediaImage.width, mediaImage.height)
+        val cropRect = Rect(0, 0, imageWidth, imageHeight)
+
+        // If the image has a way wider aspect ratio than expected, crop less of the height so we
+        // don't end up cropping too much of the image. If the image has a way taller aspect ratio
+        // than expected, we don't have to make any changes to our cropping so we don't handle it
+        // here.
+        val currentCropPercentages = imageCropPercentages.value ?: return
+        if (actualAspectRatio > 3) {
+            val originalHeightCropPercentage = currentCropPercentages.first
+            val originalWidthCropPercentage = currentCropPercentages.second
+            imageCropPercentages.value =
+                Pair(originalHeightCropPercentage / 2, originalWidthCropPercentage)
+        }
 
         // If the image is rotated by 90 (or 270) degrees, swap height and width when calculating
         // the crop.
-        val (widthCrop, heightCrop) = when(imageRotationDegrees) {
+        val cropPercentages = imageCropPercentages.value ?: return
+        val heightCropPercent = cropPercentages.first
+        val widthCropPercent = cropPercentages.second
+        val (widthCrop, heightCrop) = when (rotationDegrees) {
             90, 270 -> Pair(heightCropPercent / 100f, widthCropPercent / 100f)
             else -> Pair(widthCropPercent / 100f, heightCropPercent / 100f)
         }
+
         cropRect.inset(
-            (mediaImage.width * widthCrop / 2).toInt(),
-            (mediaImage.height * heightCrop / 2).toInt()
+            (imageWidth * widthCrop / 2).toInt(),
+            (imageHeight * heightCrop / 2).toInt()
         )
         val croppedBitmap =
-            ImageUtils.rotateAndCrop(convertImageToBitmap, imageRotationDegrees, cropRect);
+            ImageUtils.rotateAndCrop(convertImageToBitmap, rotationDegrees, cropRect);
         recognizeTextOnDevice(InputImage.fromBitmap(croppedBitmap, 0)).addOnCompleteListener {
-            isBusy = false
+            imageProxy.close()
         }
     }