(android): android performance improvements (react-native-camera#644)

* removed re-saving of output file
 * moved image processing onto an async task to allow camera to be used while processing is running

android/src/main/java/com/lwansbrough/RCTCamera/MutableImage.java

@@ -0,0 +1,285 @@
+package com.lwansbrough.RCTCamera;
+
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Matrix;
+import android.media.ExifInterface;
+import android.util.Base64;
+import android.util.Log;
+
+import com.drew.imaging.ImageMetadataReader;
+import com.drew.imaging.ImageProcessingException;
+import com.drew.metadata.Directory;
+import com.drew.metadata.Metadata;
+import com.drew.metadata.MetadataException;
+import com.drew.metadata.Tag;
+import com.drew.metadata.exif.ExifIFD0Directory;
+import com.facebook.react.bridge.ReadableMap;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+public class MutableImage {
+    private static final String TAG = "RNCamera";
+
+    private final byte[] originalImageData;
+    private Bitmap currentRepresentation;
+    private Metadata originalImageMetaData;
+    private boolean hasBeenReoriented = false;
+
+    public MutableImage(byte[] originalImageData) {
+        this.originalImageData = originalImageData;
+        this.currentRepresentation = toBitmap(originalImageData);
+    }
+
+    public void mirrorImage() throws ImageMutationFailedException {
+        Matrix m = new Matrix();
+
+        m.preScale(-1, 1);
+
+        Bitmap bitmap = Bitmap.createBitmap(
+                currentRepresentation,
+                0,
+                0,
+                currentRepresentation.getWidth(),
+                currentRepresentation.getHeight(),
+                m,
+                false
+        );
+
+        if (bitmap == null)
+            throw new ImageMutationFailedException("failed to mirror");
+
+        this.currentRepresentation = bitmap;
+    }
+
+    public void fixOrientation() throws ImageMutationFailedException {
+        try {
+            Metadata metadata = originalImageMetaData();
+
+            ExifIFD0Directory exifIFD0Directory = metadata.getFirstDirectoryOfType(ExifIFD0Directory.class);
+            if (exifIFD0Directory == null) {
+                return;
+            } else if (exifIFD0Directory.containsTag(ExifIFD0Directory.TAG_ORIENTATION)) {
+                int exifOrientation = exifIFD0Directory.getInt(ExifIFD0Directory.TAG_ORIENTATION);
+                rotate(exifOrientation);
+            }
+        } catch (ImageProcessingException | IOException | MetadataException e) {
+            throw new ImageMutationFailedException("failed to fix orientation", e);
+        }
+    }
+
+    private void rotate(int exifOrientation) throws ImageMutationFailedException {
+        final Matrix bitmapMatrix = new Matrix();
+        switch (exifOrientation) {
+            case 1:
+                break;
+            case 2:
+                bitmapMatrix.postScale(-1, 1);
+                break;
+            case 3:
+                bitmapMatrix.postRotate(180);
+                break;
+            case 4:
+                bitmapMatrix.postRotate(180);
+                bitmapMatrix.postScale(-1, 1);
+                break;
+            case 5:
+                bitmapMatrix.postRotate(90);
+                bitmapMatrix.postScale(-1, 1);
+                break;
+            case 6:
+                bitmapMatrix.postRotate(90);
+                break;
+            case 7:
+                bitmapMatrix.postRotate(270);
+                bitmapMatrix.postScale(-1, 1);
+                break;
+            case 8:
+                bitmapMatrix.postRotate(270);
+                break;
+            default:
+                break;
+        }
+
+        Bitmap transformedBitmap = Bitmap.createBitmap(
+                currentRepresentation,
+                0,
+                0,
+                currentRepresentation.getWidth(),
+                currentRepresentation.getHeight(),
+                bitmapMatrix,
+                false
+        );
+
+        if (transformedBitmap == null)
+            throw new ImageMutationFailedException("failed to rotate");
+
+        this.currentRepresentation = transformedBitmap;
+        this.hasBeenReoriented = true;
+    }
+
+    private static Bitmap toBitmap(byte[] data) {
+        try {
+            ByteArrayInputStream inputStream = new ByteArrayInputStream(data);
+            Bitmap photo = BitmapFactory.decodeStream(inputStream);
+            inputStream.close();
+            return photo;
+        } catch (IOException e) {
+            throw new IllegalStateException("Will not happen", e);
+        }
+    }
+
+    public String toBase64() {
+        return Base64.encodeToString(toBytes(currentRepresentation), Base64.DEFAULT);
+    }
+
+    public void writeDataToFile(File file, ReadableMap options) throws IOException {
+        FileOutputStream fos = new FileOutputStream(file);
+        fos.write(toBytes(currentRepresentation));
+        fos.close();
+
+        try {
+            ExifInterface exif = new ExifInterface(file.getAbsolutePath());
+
+            // copy original exif data to the output exif...
+            // unfortunately, this Android ExifInterface class doesn't understand all the tags so we lose some
+            for (Directory directory : originalImageMetaData().getDirectories()) {
+                for (Tag tag : directory.getTags()) {
+                    int tagType = tag.getTagType();
+                    Object object = directory.getObject(tagType);
+                    exif.setAttribute(tag.getTagName(), object.toString());
+                }
+            }
+
+            writeLocationExifData(options, exif);
+
+            if(hasBeenReoriented)
+                rewriteOrientation(exif);
+
+            exif.saveAttributes();
+        } catch (ImageProcessingException  | IOException e) {
+            Log.e(TAG, "failed to save exif data", e);
+        }
+    }
+
+    private void rewriteOrientation(ExifInterface exif) {
+        exif.setAttribute(ExifInterface.TAG_ORIENTATION, String.valueOf(ExifInterface.ORIENTATION_NORMAL));
+    }
+
+    private void writeLocationExifData(ReadableMap options, ExifInterface exif) {
+        if(!options.hasKey("metadata"))
+            return;
+
+        ReadableMap metadata = options.getMap("metadata");
+        if (!metadata.hasKey("location"))
+            return;
+
+        ReadableMap location = metadata.getMap("location");
+        if(!location.hasKey("coords"))
+            return;
+
+        try {
+            ReadableMap coords = location.getMap("coords");
+            double latitude = coords.getDouble("latitude");
+            double longitude = coords.getDouble("longitude");
+
+            GPS.writeExifData(latitude, longitude, exif);
+        } catch (IOException e) {
+            Log.e(TAG, "Couldn't write location data", e);
+        }
+    }
+
+    private Metadata originalImageMetaData() throws ImageProcessingException, IOException {
+        if(this.originalImageMetaData == null) {//this is expensive, don't do it more than once
+            originalImageMetaData = ImageMetadataReader.readMetadata(
+                    new BufferedInputStream(new ByteArrayInputStream(originalImageData)),
+                    originalImageData.length
+            );
+        }
+        return originalImageMetaData;
+    }
+
+    private static byte[] toBytes(Bitmap image) {
+        byte[] result = null;
+
+        try {
+            result = toJpeg(image, 85);
+        } catch (OutOfMemoryError e) {
+            try {
+                result = toJpeg(image, 70);
+            } catch (OutOfMemoryError e2) {
+                e.printStackTrace();
+            }
+        }
+
+        return result;
+    }
+
+    private static byte[] toJpeg(Bitmap bitmap, int quality) throws OutOfMemoryError {
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        bitmap.compress(Bitmap.CompressFormat.JPEG, quality, outputStream);
+
+        try {
+            return outputStream.toByteArray();
+        } finally {
+            try {
+                outputStream.close();
+            } catch (IOException e) {
+                Log.e(TAG, "problem compressing jpeg", e);
+            }
+        }
+    }
+
+    public static class ImageMutationFailedException extends Exception {
+        public ImageMutationFailedException(String detailMessage, Throwable throwable) {
+            super(detailMessage, throwable);
+        }
+
+        public ImageMutationFailedException(String detailMessage) {
+            super(detailMessage);
+        }
+    }
+
+    private static class GPS {
+        public static void writeExifData(double latitude, double longitude, ExifInterface exif) throws IOException {
+            exif.setAttribute(ExifInterface.TAG_GPS_LATITUDE, toDegreeMinuteSecods(latitude));
+            exif.setAttribute(ExifInterface.TAG_GPS_LATITUDE_REF, latitudeRef(latitude));
+            exif.setAttribute(ExifInterface.TAG_GPS_LONGITUDE, toDegreeMinuteSecods(longitude));
+            exif.setAttribute(ExifInterface.TAG_GPS_LONGITUDE_REF, longitudeRef(longitude));
+        }
+
+        private static String latitudeRef(double latitude) {
+            return latitude < 0.0d ? "S" : "N";
+        }
+
+        private static String longitudeRef(double longitude) {
+            return longitude < 0.0d ? "W" : "E";
+        }
+
+        private static String toDegreeMinuteSecods(double latitude) {
+            latitude = Math.abs(latitude);
+            int degree = (int) latitude;
+            latitude *= 60;
+            latitude -= (degree * 60.0d);
+            int minute = (int) latitude;
+            latitude *= 60;
+            latitude -= (minute * 60.0d);
+            int second = (int) (latitude * 1000.0d);
+
+            StringBuffer sb = new StringBuffer();
+            sb.append(degree);
+            sb.append("/1,");
+            sb.append(minute);
+            sb.append("/1,");
+            sb.append(second);
+            sb.append("/1000,");
+            return sb.toString();
+        }
+    }
+}