content: /*
   * Copyright 2014 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.hardware.camera2;
  
  import android.annotation.IntRange;
  import android.annotation.NonNull;
  import android.graphics.Bitmap;
  import android.graphics.Color;
  import android.graphics.ImageFormat;
  import android.hardware.camera2.impl.CameraMetadataNative;
  import android.location.Location;
  import android.media.ExifInterface;
  import android.media.Image;
  import android.os.SystemClock;
  import android.util.Log;
  import android.util.Size;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  import java.text.DateFormat;
  import java.text.SimpleDateFormat;
  import java.util.Calendar;
  import java.util.Locale;
  import java.util.TimeZone;
  
  /**
   * The {@link DngCreator} class provides functions to write raw pixel data as a DNG file.
   *
   * <p>
   * This class is designed to be used with the {@link android.graphics.ImageFormat#RAW_SENSOR}
   * buffers available from {@link android.hardware.camera2.CameraDevice}, or with Bayer-type raw
   * pixel data that is otherwise generated by an application.  The DNG metadata tags will be
   * generated from a {@link android.hardware.camera2.CaptureResult} object or set directly.
   * </p>
   *
   * <p>
   * The DNG file format is a cross-platform file format that is used to store pixel data from
   * camera sensors with minimal pre-processing applied.  DNG files allow for pixel data to be
   * defined in a user-defined colorspace, and have associated metadata that allow for this
   * pixel data to be converted to the standard CIE XYZ colorspace during post-processing.
   * </p>
   *
   * <p>
   * For more information on the DNG file format and associated metadata, please refer to the
   * <a href=
   * "https://wwwimages2.adobe.com/content/dam/Adobe/en/products/photoshop/pdfs/dng_spec_1.4.0.0.pdf">
   * Adobe DNG 1.4.0.0 specification</a>.
   * </p>
   */
  public final class DngCreator implements AutoCloseable {
  
      private static final String TAG = "DngCreator";
      /**
       * Create a new DNG object.
       *
       * <p>
       * It is not necessary to call any set methods to write a well-formatted DNG file.
       * </p>
       * <p>
       * DNG metadata tags will be generated from the corresponding parameters in the
       * {@link android.hardware.camera2.CaptureResult} object.
       * </p>
       * <p>
       * For best quality DNG files, it is strongly recommended that lens shading map output is
       * enabled if supported. See {@link CaptureRequest#STATISTICS_LENS_SHADING_MAP_MODE}.
       * </p>
       * @param characteristics an object containing the static
       *          {@link android.hardware.camera2.CameraCharacteristics}.
       * @param metadata a metadata object to generate tags from.
       */
      public DngCreator(@NonNull CameraCharacteristics characteristics,
              @NonNull CaptureResult metadata) {
          if (characteristics == null || metadata == null) {
              throw new IllegalArgumentException("Null argument to DngCreator constructor");
          }
  
          // Find current time in milliseconds since 1970
          long currentTime = System.currentTimeMillis();
          // Assume that sensor timestamp has that timebase to start
          long timeOffset = 0;
  
          int timestampSource = characteristics.get(
                  CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE);
  
          if (timestampSource == CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE_REALTIME) {
              // This means the same timebase as SystemClock.elapsedRealtime(),
              // which is CLOCK_BOOTTIME
              timeOffset = currentTime - SystemClock.elapsedRealtime();
          } else if (timestampSource == CameraCharacteristics.SENSOR_INFO_TIMESTAMP_SOURCE_UNKNOWN) {
              // This means the same timebase as System.currentTimeMillis(),
              // which is CLOCK_MONOTONIC
              timeOffset = currentTime - SystemClock.uptimeMillis();
          } else {
              // Unexpected time source - treat as CLOCK_MONOTONIC
              Log.w(TAG, "Sensor timestamp source is unexpected: " + timestampSource);
              timeOffset = currentTime - SystemClock.uptimeMillis();
          }
  
          // Find capture time (nanos since boot)
          Long timestamp = metadata.get(CaptureResult.SENSOR_TIMESTAMP);
          long captureTime = currentTime;
          if (timestamp != null) {
              captureTime = timestamp / 1000000 + timeOffset;
          }
  
          // Create this fresh each time since the time zone may change while a long-running application
          // is active.
          final DateFormat dateTimeStampFormat =
                  new SimpleDateFormat(TIFF_DATETIME_FORMAT, Locale.US);
          dateTimeStampFormat.setTimeZone(TimeZone.getDefault());
  
          // Format for metadata
          String formattedCaptureTime = dateTimeStampFormat.format(captureTime);
  
          nativeInit(characteristics.getNativeCopy(), metadata.getNativeCopy(),
                  formattedCaptureTime);
      }
  
      /**
       * Set the orientation value to write.
       *
       * <p>
       * This will be written as the TIFF "Orientation" tag {@code (0x0112)}.
       * Calling this will override any prior settings for this tag.
       * </p>
       *
       * @param orientation the orientation value to set, one of:
       *                    <ul>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_NORMAL}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_FLIP_HORIZONTAL}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_ROTATE_180}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_FLIP_VERTICAL}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_TRANSPOSE}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_ROTATE_90}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_TRANSVERSE}</li>
       *                      <li>{@link android.media.ExifInterface#ORIENTATION_ROTATE_270}</li>
       *                    </ul>
       * @return this {@link #DngCreator} object.
       */
      @NonNull
      public DngCreator setOrientation(int orientation) {
          if (orientation < ExifInterface.ORIENTATION_UNDEFINED ||
                  orientation > ExifInterface.ORIENTATION_ROTATE_270) {
              throw new IllegalArgumentException("Orientation " + orientation +
                      " is not a valid EXIF orientation value");
          }
          // ExifInterface and TIFF/EP spec differ on definition of
          // "Unknown" orientation; other values map directly
          if (orientation == ExifInterface.ORIENTATION_UNDEFINED) {
              orientation = TAG_ORIENTATION_UNKNOWN;
          }
          nativeSetOrientation(orientation);
          return this;
      }
  
      /**
       * Set the thumbnail image.
       *
       * <p>
       * Pixel data will be converted to a Baseline TIFF RGB image, with 8 bits per color channel.
       * The alpha channel will be discarded.  Thumbnail images with a dimension larger than
       * {@link #MAX_THUMBNAIL_DIMENSION} will be rejected.
       * </p>
       *
       * @param pixels a {@link android.graphics.Bitmap} of pixel data.
       * @return this {@link #DngCreator} object.
       * @throws java.lang.IllegalArgumentException if the given thumbnail image has a dimension
       *      larger than {@link #MAX_THUMBNAIL_DIMENSION}.
       */
      @NonNull
      public DngCreator setThumbnail(@NonNull Bitmap pixels) {
          if (pixels == null) {
              throw new IllegalArgumentException("Null argument to setThumbnail");
          }
  
          int width = pixels.getWidth();
          int height = pixels.getHeight();
  
          if (width > MAX_THUMBNAIL_DIMENSION || height > MAX_THUMBNAIL_DIMENSION) {
              throw new IllegalArgumentException("Thumbnail dimensions width,height (" + width +
                      "," + height + ") too large, dimensions must be smaller than " +
                      MAX_THUMBNAIL_DIMENSION);
          }
  
          ByteBuffer rgbBuffer = convertToRGB(pixels);
          nativeSetThumbnail(rgbBuffer, width, height);
  
          return this;
      }
  
      /**
       * Set the thumbnail image.
       *
       * <p>
       * Pixel data is interpreted as a {@link android.graphics.ImageFormat#YUV_420_888} image.
       * Thumbnail images with a dimension larger than {@link #MAX_THUMBNAIL_DIMENSION} will be
       * rejected.
       * </p>
       *
       * @param pixels an {@link android.media.Image} object with the format
       *               {@link android.graphics.ImageFormat#YUV_420_888}.
       * @return this {@link #DngCreator} object.
       * @throws java.lang.IllegalArgumentException if the given thumbnail image has a dimension
       *      larger than {@link #MAX_THUMBNAIL_DIMENSION}.
       */
      @NonNull
      public DngCreator setThumbnail(@NonNull Image pixels) {
          if (pixels == null) {
              throw new IllegalArgumentException("Null argument to setThumbnail");
          }
  
          int format = pixels.getFormat();
          if (format != ImageFormat.YUV_420_888) {
              throw new IllegalArgumentException("Unsupported Image format " + format);
          }
  
          int width = pixels.getWidth();
          int height = pixels.getHeight();
  
          if (width > MAX_THUMBNAIL_DIMENSION || height > MAX_THUMBNAIL_DIMENSION) {
              throw new IllegalArgumentException("Thumbnail dimensions width,height (" + width +
                      "," + height + ") too large, dimensions must be smaller than " +
                      MAX_THUMBNAIL_DIMENSION);
          }
  
          ByteBuffer rgbBuffer = convertToRGB(pixels);
          nativeSetThumbnail(rgbBuffer, width, height);
  
          return this;
      }
  
      /**
       * Set image location metadata.
       *
       * <p>
       * The given location object must contain at least a valid time, latitude, and longitude
       * (equivalent to the values returned by {@link android.location.Location#getTime()},
       * {@link android.location.Location#getLatitude()}, and
       * {@link android.location.Location#getLongitude()} methods).
       * </p>
       *
       * @param location an {@link android.location.Location} object to set.
       * @return this {@link #DngCreator} object.
       *
       * @throws java.lang.IllegalArgumentException if the given location object doesn't
       *          contain enough information to set location metadata.
       */
      @NonNull
      public DngCreator setLocation(@NonNull Location location) {
          if (location == null) {
              throw new IllegalArgumentException("Null location passed to setLocation");
          }
          double latitude = location.getLatitude();
          double longitude = location.getLongitude();
          long time = location.getTime();
  
          int[] latTag = toExifLatLong(latitude);
          int[] longTag = toExifLatLong(longitude);
          String latRef = latitude >= 0 ? GPS_LAT_REF_NORTH : GPS_LAT_REF_SOUTH;
          String longRef = longitude >= 0 ? GPS_LONG_REF_EAST : GPS_LONG_REF_WEST;
  
          String dateTag = sExifGPSDateStamp.format(time);
          mGPSTimeStampCalendar.setTimeInMillis(time);
          int[] timeTag = new int[] { mGPSTimeStampCalendar.get(Calendar.HOUR_OF_DAY), 1,
                  mGPSTimeStampCalendar.get(Calendar.MINUTE), 1,
                  mGPSTimeStampCalendar.get(Calendar.SECOND), 1 };
          nativeSetGpsTags(latTag, latRef, longTag, longRef, dateTag, timeTag);
          return this;
      }
  
      /**
       * Set the user description string to write.
       *
       * <p>
       * This is equivalent to setting the TIFF "ImageDescription" tag {@code (0x010E)}.
       * </p>
       *
       * @param description the user description string.
       * @return this {@link #DngCreator} object.
       */
      @NonNull
      public DngCreator setDescription(@NonNull String description) {
          if (description == null) {
              throw new IllegalArgumentException("Null description passed to setDescription.");
          }
          nativeSetDescription(description);
          return this;
      }
  
      /**
       * Write the {@link android.graphics.ImageFormat#RAW_SENSOR} pixel data to a DNG file with
       * the currently configured metadata.
       *
       * <p>
       * Raw pixel data must have 16 bits per pixel, and the input must contain at least
       * {@code offset + 2 * width * height)} bytes.  The width and height of
       * the input are taken from the width and height set in the {@link DngCreator} metadata tags,
       * and will typically be equal to the width and height of
       * {@link CameraCharacteristics#SENSOR_INFO_PRE_CORRECTION_ACTIVE_ARRAY_SIZE}.  Prior to
       * API level 23, this was always the same as
       * {@link CameraCharacteristics#SENSOR_INFO_ACTIVE_ARRAY_SIZE}.
       * The pixel layout in the input is determined from the reported color filter arrangement (CFA)
       * set in {@link CameraCharacteristics#SENSOR_INFO_COLOR_FILTER_ARRANGEMENT}.  If insufficient
       * metadata is available to write a well-formatted DNG file, an
       * {@link java.lang.IllegalStateException} will be thrown.
       * </p>
       *
       * @param dngOutput an {@link java.io.OutputStream} to write the DNG file to.
       * @param size the {@link Size} of the image to write, in pixels.
       * @param pixels an {@link java.io.InputStream} of pixel data to write.
       * @param offset the offset of the raw image in bytes.  This indicates how many bytes will
       *               be skipped in the input before any pixel data is read.
       *
       * @throws IOException if an error was encountered in the input or output stream.
       * @throws java.lang.IllegalStateException if not enough metadata information has been
       *          set to write a well-formatted DNG file.
       * @throws java.lang.IllegalArgumentException if the size passed in does not match the
       */
      public void writeInputStream(@NonNull OutputStream dngOutput, @NonNull Size size,
              @NonNull InputStream pixels, @IntRange(from=0) long offset) throws IOException {
          if (dngOutput == null) {
              throw new IllegalArgumentException("Null dngOutput passed to writeInputStream");
          } else if (size == null) {
              throw new IllegalArgumentException("Null size passed to writeInputStream");
          } else if (pixels == null) {
              throw new IllegalArgumentException("Null pixels passed to writeInputStream");
          } else if (offset < 0) {
              throw new IllegalArgumentException("Negative offset passed to writeInputStream");
          }
  
          int width = size.getWidth();
          int height = size.getHeight();
          if (width <= 0 || height <= 0) {
              throw new IllegalArgumentException("Size with invalid width, height: (" + width + "," +
                      height + ") passed to writeInputStream");
          }
          nativeWriteInputStream(dngOutput, pixels, width, height, offset);
      }
  
      /**
       * Write the {@link android.graphics.ImageFormat#RAW_SENSOR} pixel data to a DNG file with
       * the currently configured metadata.
       *
       * <p>
       * Raw pixel data must have 16 bits per pixel, and the input must contain at least
       * {@code offset + 2 * width * height)} bytes.  The width and height of
       * the input are taken from the width and height set in the {@link DngCreator} metadata tags,
       * and will typically be equal to the width and height of
       * {@link CameraCharacteristics#SENSOR_INFO_PRE_CORRECTION_ACTIVE_ARRAY_SIZE}.  Prior to
       * API level 23, this was always the same as
       * {@link CameraCharacteristics#SENSOR_INFO_ACTIVE_ARRAY_SIZE}.
       * The pixel layout in the input is determined from the reported color filter arrangement (CFA)
       * set in {@link CameraCharacteristics#SENSOR_INFO_COLOR_FILTER_ARRANGEMENT}.  If insufficient
       * metadata is available to write a well-formatted DNG file, an
       * {@link java.lang.IllegalStateException} will be thrown.
       * </p>
       *
       * <p>
       * Any mark or limit set on this {@link ByteBuffer} is ignored, and will be cleared by this
       * method.
       * </p>
       *
       * @param dngOutput an {@link java.io.OutputStream} to write the DNG file to.
       * @param size the {@link Size} of the image to write, in pixels.
       * @param pixels an {@link java.nio.ByteBuffer} of pixel data to write.
       * @param offset the offset of the raw image in bytes.  This indicates how many bytes will
       *               be skipped in the input before any pixel data is read.
       *
       * @throws IOException if an error was encountered in the input or output stream.
       * @throws java.lang.IllegalStateException if not enough metadata information has been
       *          set to write a well-formatted DNG file.
       */
      public void writeByteBuffer(@NonNull OutputStream dngOutput, @NonNull Size size,
              @NonNull ByteBuffer pixels, @IntRange(from=0) long offset)
              throws IOException {
          if (dngOutput == null) {
              throw new IllegalArgumentException("Null dngOutput passed to writeByteBuffer");
          } else if (size == null) {
              throw new IllegalArgumentException("Null size passed to writeByteBuffer");
          } else if (pixels == null) {
              throw new IllegalArgumentException("Null pixels passed to writeByteBuffer");
          } else if (offset < 0) {
              throw new IllegalArgumentException("Negative offset passed to writeByteBuffer");
          }
  
          int width = size.getWidth();
          int height = size.getHeight();
  
          writeByteBuffer(width, height, pixels, dngOutput, DEFAULT_PIXEL_STRIDE,
                  width * DEFAULT_PIXEL_STRIDE, offset);
      }
  
      /**
       * Write the pixel data to a DNG file with the currently configured metadata.
       *
       * <p>
       * For this method to succeed, the {@link android.media.Image} input must contain
       * {@link android.graphics.ImageFormat#RAW_SENSOR} pixel data, otherwise an
       * {@link java.lang.IllegalArgumentException} will be thrown.
       * </p>
       *
       * @param dngOutput an {@link java.io.OutputStream} to write the DNG file to.
       * @param pixels an {@link android.media.Image} to write.
       *
       * @throws java.io.IOException if an error was encountered in the output stream.
       * @throws java.lang.IllegalArgumentException if an image with an unsupported format was used.
       * @throws java.lang.IllegalStateException if not enough metadata information has been
       *          set to write a well-formatted DNG file.
       */
      public void writeImage(@NonNull OutputStream dngOutput, @NonNull Image pixels)
              throws IOException {
          if (dngOutput == null) {
              throw new IllegalArgumentException("Null dngOutput to writeImage");
          } else if (pixels == null) {
              throw new IllegalArgumentException("Null pixels to writeImage");
          }
  
          int format = pixels.getFormat();
          if (format != ImageFormat.RAW_SENSOR) {
              throw new IllegalArgumentException("Unsupported image format " + format);
          }
  
          Image.Plane[] planes = pixels.getPlanes();
          if (planes == null || planes.length <= 0) {
              throw new IllegalArgumentException("Image with no planes passed to writeImage");
          }
  
          ByteBuffer buf = planes[0].getBuffer();
          writeByteBuffer(pixels.getWidth(), pixels.getHeight(), buf, dngOutput,
                  planes[0].getPixelStride(), planes[0].getRowStride(), 0);
      }
  
      @Override
      public void close() {
          nativeDestroy();
      }
  
      /**
       * Max width or height dimension for thumbnails.
       */
      public static final int MAX_THUMBNAIL_DIMENSION = 256; // max pixel dimension for TIFF/EP
  
      @Override
      protected void finalize() throws Throwable {
          try {
              close();
          } finally {
              super.finalize();
          }
      }
  
      private static final String GPS_LAT_REF_NORTH = "N";
      private static final String GPS_LAT_REF_SOUTH = "S";
      private static final String GPS_LONG_REF_EAST = "E";
      private static final String GPS_LONG_REF_WEST = "W";
  
      private static final String GPS_DATE_FORMAT_STR = "yyyy:MM:dd";
      private static final String TIFF_DATETIME_FORMAT = "yyyy:MM:dd HH:mm:ss";
      private static final DateFormat sExifGPSDateStamp =
              new SimpleDateFormat(GPS_DATE_FORMAT_STR, Locale.US);
      private final Calendar mGPSTimeStampCalendar = Calendar
              .getInstance(TimeZone.getTimeZone("UTC"));
  
      static {
          sExifGPSDateStamp.setTimeZone(TimeZone.getTimeZone("UTC"));
      }
  
      private static final int DEFAULT_PIXEL_STRIDE = 2; // bytes per sample
      private static final int BYTES_PER_RGB_PIX = 3; // byts per pixel
  
      // TIFF tag values needed to map between public API and TIFF spec
      private static final int TAG_ORIENTATION_UNKNOWN = 9;
  
      /**
       * Offset, rowStride, and pixelStride are given in bytes.  Height and width are given in pixels.
       */
      private void writeByteBuffer(int width, int height, ByteBuffer pixels, OutputStream dngOutput,
                                   int pixelStride, int rowStride, long offset)  throws IOException {
          if (width <= 0 || height <= 0) {
              throw new IllegalArgumentException("Image with invalid width, height: (" + width + "," +
                      height + ") passed to write");
          }
          long capacity = pixels.capacity();
          long totalSize = ((long) rowStride) * height + offset;
          if (capacity < totalSize) {
              throw new IllegalArgumentException("Image size " + capacity +
                      " is too small (must be larger than " + totalSize + ")");
          }
          int minRowStride = pixelStride * width;
          if (minRowStride > rowStride) {
              throw new IllegalArgumentException("Invalid image pixel stride, row byte width " +
                      minRowStride + " is too large, expecting " + rowStride);
          }
          pixels.clear(); // Reset mark and limit
          nativeWriteImage(dngOutput, width, height, pixels, rowStride, pixelStride, offset,
                  pixels.isDirect());
          pixels.clear();
      }
  
      /**
       * Convert a single YUV pixel to RGB.
       */
      private static void yuvToRgb(byte[] yuvData, int outOffset, /*out*/byte[] rgbOut) {
          final int COLOR_MAX = 255;
  
          float y = yuvData[0] & 0xFF;  // Y channel
          float cb = yuvData[1] & 0xFF; // U channel
          float cr = yuvData[2] & 0xFF; // V channel
  
          // convert YUV -> RGB (from JFIF's "Conversion to and from RGB" section)
          float r = y + 1.402f * (cr - 128);
          float g = y - 0.34414f * (cb - 128) - 0.71414f * (cr - 128);
          float b = y + 1.772f * (cb - 128);
  
          // clamp to [0,255]
          rgbOut[outOffset] = (byte) Math.max(0, Math.min(COLOR_MAX, r));
          rgbOut[outOffset + 1] = (byte) Math.max(0, Math.min(COLOR_MAX, g));
          rgbOut[outOffset + 2] = (byte) Math.max(0, Math.min(COLOR_MAX, b));
      }
  
      /**
       * Convert a single {@link Color} pixel to RGB.
       */
      private static void colorToRgb(int color, int outOffset, /*out*/byte[] rgbOut) {
          rgbOut[outOffset] = (byte) Color.red(color);
          rgbOut[outOffset + 1] = (byte) Color.green(color);
          rgbOut[outOffset + 2] = (byte) Color.blue(color);
          // Discards Alpha
      }
  
      /**
       * Generate a direct RGB {@link ByteBuffer} from a YUV420_888 {@link Image}.
       */
      private static ByteBuffer convertToRGB(Image yuvImage) {
          // TODO: Optimize this with renderscript intrinsic.
          int width = yuvImage.getWidth();
          int height = yuvImage.getHeight();
          ByteBuffer buf = ByteBuffer.allocateDirect(BYTES_PER_RGB_PIX * width * height);
  
          Image.Plane yPlane = yuvImage.getPlanes()[0];
          Image.Plane uPlane = yuvImage.getPlanes()[1];
          Image.Plane vPlane = yuvImage.getPlanes()[2];
  
          ByteBuffer yBuf = yPlane.getBuffer();
          ByteBuffer uBuf = uPlane.getBuffer();
          ByteBuffer vBuf = vPlane.getBuffer();
  
          yBuf.rewind();
          uBuf.rewind();
          vBuf.rewind();
  
          int yRowStride = yPlane.getRowStride();
          int vRowStride = vPlane.getRowStride();
          int uRowStride = uPlane.getRowStride();
  
          int yPixStride = yPlane.getPixelStride();
          int vPixStride = vPlane.getPixelStride();
          int uPixStride = uPlane.getPixelStride();
  
          byte[] yuvPixel = { 0, 0, 0 };
          byte[] yFullRow = new byte[yPixStride * (width - 1) + 1];
          byte[] uFullRow = new byte[uPixStride * (width / 2 - 1) + 1];
          byte[] vFullRow = new byte[vPixStride * (width / 2 - 1) + 1];
          byte[] finalRow = new byte[BYTES_PER_RGB_PIX * width];
          for (int i = 0; i < height; i++) {
              int halfH = i / 2;
              yBuf.position(yRowStride * i);
              yBuf.get(yFullRow);
              uBuf.position(uRowStride * halfH);
              uBuf.get(uFullRow);
              vBuf.position(vRowStride * halfH);
              vBuf.get(vFullRow);
              for (int j = 0; j < width; j++) {
                  int halfW = j / 2;
                  yuvPixel[0] = yFullRow[yPixStride * j];
                  yuvPixel[1] = uFullRow[uPixStride * halfW];
                  yuvPixel[2] = vFullRow[vPixStride * halfW];
                  yuvToRgb(yuvPixel, j * BYTES_PER_RGB_PIX, /*out*/finalRow);
              }
              buf.put(finalRow);
          }
  
          yBuf.rewind();
          uBuf.rewind();
          vBuf.rewind();
          buf.rewind();
          return buf;
      }
  
      /**
       * Generate a direct RGB {@link ByteBuffer} from a {@link Bitmap}.
       */
      private static ByteBuffer convertToRGB(Bitmap argbBitmap) {
          // TODO: Optimize this.
          int width = argbBitmap.getWidth();
          int height = argbBitmap.getHeight();
          ByteBuffer buf = ByteBuffer.allocateDirect(BYTES_PER_RGB_PIX * width * height);
  
          int[] pixelRow = new int[width];
          byte[] finalRow = new byte[BYTES_PER_RGB_PIX * width];
          for (int i = 0; i < height; i++) {
              argbBitmap.getPixels(pixelRow, /*offset*/0, /*stride*/width, /*x*/0, /*y*/i,
                      /*width*/width, /*height*/1);
              for (int j = 0; j < width; j++) {
                  colorToRgb(pixelRow[j], j * BYTES_PER_RGB_PIX, /*out*/finalRow);
              }
              buf.put(finalRow);
          }
  
          buf.rewind();
          return buf;
      }
  
      /**
       * Convert coordinate to EXIF GPS tag format.
       */
      private static int[] toExifLatLong(double value) {
          // convert to the format dd/1 mm/1 ssss/100
          value = Math.abs(value);
          int degrees = (int) value;
          value = (value - degrees) * 60;
          int minutes = (int) value;
          value = (value - minutes) * 6000;
          int seconds = (int) value;
          return new int[] { degrees, 1, minutes, 1, seconds, 100 };
      }
  
      /**
       * This field is used by native code, do not access or modify.
       */
      private long mNativeContext;
  
      private static native void nativeClassInit();
  
      private synchronized native void nativeInit(CameraMetadataNative nativeCharacteristics,
                                                  CameraMetadataNative nativeResult,
                                                  String captureTime);
  
      private synchronized native void nativeDestroy();
  
      private synchronized native void nativeSetOrientation(int orientation);
  
      private synchronized native void nativeSetDescription(String description);
  
      private synchronized native void nativeSetGpsTags(int[] latTag, String latRef, int[] longTag,
                                                        String longRef, String dateTag,
                                                        int[] timeTag);
  
      private synchronized native void nativeSetThumbnail(ByteBuffer buffer, int width, int height);
  
      private synchronized native void nativeWriteImage(OutputStream out, int width, int height,
                                                        ByteBuffer rawBuffer, int rowStride,
                                                        int pixStride, long offset, boolean isDirect)
                                                        throws IOException;
  
      private synchronized native void nativeWriteInputStream(OutputStream out, InputStream rawStream,
                                                              int width, int height, long offset)
                                                              throws IOException;
  
      static {
          nativeClassInit();
      }
  }
  