Adds better error handling for image format YUV_420_888.

This format can not be read by the InputImage.fromByteArray API, as documented at https://developers.google.com/android/reference/com/google/mlkit/vision/common/InputImage#public-static-inputimage-frombytearray-byte[]-bytearray,-int-width,-int-height,-int-rotationdegrees,-int-format.

Converting the bytes received here to the right type (android.media.Image) is non-trivial.

Additionally improving error handling by passing along stack traces when possible.

packages/google_mlkit_commons/android/src/main/java/com/google_mlkit_commons/InputImageConverter.java

@@ -1,6 +1,7 @@
 package com.google_mlkit_commons;
 
 import android.content.Context;
+import android.graphics.ImageFormat;
 import android.net.Uri;
 import android.util.Log;
 
@@ -17,8 +18,8 @@ public class InputImageConverter {
 
     //Returns an [InputImage] from the image data received
     public static InputImage getInputImageFromData(Map<String, Object> imageData,
-                                                   Context context,
-                                                   MethodChannel.Result result) {
+            Context context,
+            MethodChannel.Result result) {
         //Differentiates whether the image data is a path for a image file or contains image data in form of bytes
         String model = (String) imageData.get("type");
         InputImage inputImage;
@@ -29,7 +30,7 @@ public static InputImage getInputImageFromData(Map<String, Object> imageData,
             } catch (IOException e) {
                 Log.e("ImageError", "Getting Image failed");
                 Log.e("ImageError", e.toString());
-                result.error("InputImageConverterError", e.toString(), null);
+                result.error("InputImageConverterError", e.toString(), e);
                 return null;
             }
         } else {
@@ -39,16 +40,28 @@ public static InputImage getInputImageFromData(Map<String, Object> imageData,
                     Map<String, Object> metaData = (Map<String, Object>) imageData.get("metadata");
 
                     assert metaData != null;
-                    inputImage = InputImage.fromByteArray((byte[]) Objects.requireNonNull(imageData.get("bytes")),
-                            Double.valueOf(Objects.requireNonNull(metaData.get("width")).toString()).intValue(),
-                            Double.valueOf(Objects.requireNonNull(metaData.get("height")).toString()).intValue(),
-                            Integer.parseInt(Objects.requireNonNull(metaData.get("rotation")).toString()),
-                            Integer.parseInt(Objects.requireNonNull(metaData.get("image_format")).toString()));
-                    return inputImage;
+                    byte[] data = (byte[]) Objects.requireNonNull(imageData.get("bytes"));
+                    int imageFormat = Integer.parseInt(Objects.requireNonNull(metaData.get("image_format")).toString());
+                    int rotationDegrees = Integer.parseInt(Objects.requireNonNull(metaData.get("rotation")).toString());
+                    int width = Double.valueOf(Objects.requireNonNull(metaData.get("width")).toString()).intValue();
+                    int height = Double.valueOf(Objects.requireNonNull(metaData.get("height")).toString()).intValue();
+                    if (imageFormat == ImageFormat.NV21 || imageFormat == ImageFormat.YV1) {
+                        return InputImage.fromByteArray(
+                                data,
+                                width,
+                                height,
+                                rotationDegrees,
+                                imageFormat);
+                    }
+                    result.error("InputImageConverterError", "ImageFormat is not supported.", null);
+                    // TODO: Use InputImage.fromMediaImage, which supports more types, e.g. IMAGE_FORMAT_YUV_420_888.
+                    // See https://developers.google.com/android/reference/com/google/mlkit/vision/common/InputImage#fromMediaImage(android.media.Image,%20int)
+                    return null;
+
                 } catch (Exception e) {
                     Log.e("ImageError", "Getting Image failed");
                     Log.e("ImageError", e.toString());
-                    result.error("InputImageConverterError", e.toString(), null);
+                    result.error("InputImageConverterError", e.toString(), e);
                     return null;
                 }
             } else {