camera/camera-core/src/main/java/androidx/camera/core/internal/utils/ImageUtil.java - platform/frameworks/support - Git at Google

 /*
  * Copyright 2020 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 androidx.camera.core.internal.utils;

 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.BitmapRegionDecoder;
 import android.graphics.ImageFormat;
 import android.graphics.Matrix;
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.YuvImage;
 import android.util.Rational;
 import android.util.Size;

 import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.camera.core.ImageProxy;
 import androidx.camera.core.Logger;

 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;

 /**
  * Utility class for image related operations.
  */
 @RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
 public final class ImageUtil {
  private static final String TAG = "ImageUtil";

  private ImageUtil() {
  }

  /**
  * Converts a {@link Size} to an float array of vertexes.
  */
  @NonNull
  public static float[] sizeToVertexes(@NonNull Size size) {
  return new float[]{0, 0, size.getWidth(), 0, size.getWidth(), size.getHeight(), 0,
  size.getHeight()};
  }

  /**
  * Returns the min value.
  */
  public static float min(float value1, float value2, float value3, float value4) {
  return Math.min(Math.min(value1, value2), Math.min(value3, value4));
  }

  /**
  * Rotates aspect ratio based on rotation degrees.
  */
  @NonNull
  public static Rational getRotatedAspectRatio(
  @IntRange(from = 0, to = 359) int rotationDegrees,
  @NonNull Rational aspectRatio) {
  if (rotationDegrees == 90 || rotationDegrees == 270) {
  return inverseRational(aspectRatio);
  }

  return new Rational(aspectRatio.getNumerator(), aspectRatio.getDenominator());
  }

  /**
  * Converts JPEG {@link ImageProxy} to JPEG byte array.
  */
  @NonNull
  public static byte[] jpegImageToJpegByteArray(@NonNull ImageProxy image) {
  if (image.getFormat() != ImageFormat.JPEG) {
  throw new IllegalArgumentException(
  "Incorrect image format of the input image proxy: " + image.getFormat());
  }

  ImageProxy.PlaneProxy[] planes = image.getPlanes();
  ByteBuffer buffer = planes[0].getBuffer();
  byte[] data = new byte[buffer.capacity()];
  buffer.rewind();
  buffer.get(data);

  return data;
  }

  /**
  * Converts JPEG {@link ImageProxy} to JPEG byte array. The input JPEG image will be cropped
  * by the specified crop rectangle and compressed by the specified quality value.
  */
  @NonNull
  public static byte[] jpegImageToJpegByteArray(@NonNull ImageProxy image,
  @NonNull Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
  throws CodecFailedException {
  if (image.getFormat() != ImageFormat.JPEG) {
  throw new IllegalArgumentException(
  "Incorrect image format of the input image proxy: " + image.getFormat());
  }

  byte[] data = jpegImageToJpegByteArray(image);
  data = cropJpegByteArray(data, cropRect, jpegQuality);

  return data;
  }

  /**
  * Converts YUV_420_888 {@link ImageProxy} to JPEG byte array. The input YUV_420_888 image
  * will be cropped if a non-null crop rectangle is specified. The output JPEG byte array will
  * be compressed by the specified quality value.
  */
  @NonNull
  public static byte[] yuvImageToJpegByteArray(@NonNull ImageProxy image,
  @Nullable Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
  throws CodecFailedException {
  if (image.getFormat() != ImageFormat.YUV_420_888) {
  throw new IllegalArgumentException(
  "Incorrect image format of the input image proxy: " + image.getFormat());
  }

  return ImageUtil.nv21ToJpeg(
  ImageUtil.yuv_420_888toNv21(image),
  image.getWidth(),
  image.getHeight(),
  cropRect,
  jpegQuality);
  }

  /** {@link android.media.Image} to NV21 byte array. */
  @NonNull
  public static byte[] yuv_420_888toNv21(@NonNull ImageProxy image) {
  ImageProxy.PlaneProxy yPlane = image.getPlanes()[0];
  ImageProxy.PlaneProxy uPlane = image.getPlanes()[1];
  ImageProxy.PlaneProxy vPlane = image.getPlanes()[2];

  ByteBuffer yBuffer = yPlane.getBuffer();
  ByteBuffer uBuffer = uPlane.getBuffer();
  ByteBuffer vBuffer = vPlane.getBuffer();
  yBuffer.rewind();
  uBuffer.rewind();
  vBuffer.rewind();

  int ySize = yBuffer.remaining();

  int position = 0;
  // TODO(b/115743986): Pull these bytes from a pool instead of allocating for every image.
  byte[] nv21 = new byte[ySize + (image.getWidth() * image.getHeight() / 2)];

  // Add the full y buffer to the array. If rowStride > 1, some padding may be skipped.
  for (int row = 0; row < image.getHeight(); row++) {
  yBuffer.get(nv21, position, image.getWidth());
  position += image.getWidth();
  yBuffer.position(
  Math.min(ySize, yBuffer.position() - image.getWidth() + yPlane.getRowStride()));
  }

  int chromaHeight = image.getHeight() / 2;
  int chromaWidth = image.getWidth() / 2;
  int vRowStride = vPlane.getRowStride();
  int uRowStride = uPlane.getRowStride();
  int vPixelStride = vPlane.getPixelStride();
  int uPixelStride = uPlane.getPixelStride();

  // Interleave the u and v frames, filling up the rest of the buffer. Use two line buffers to
  // perform faster bulk gets from the byte buffers.
  byte[] vLineBuffer = new byte[vRowStride];
  byte[] uLineBuffer = new byte[uRowStride];
  for (int row = 0; row < chromaHeight; row++) {
  vBuffer.get(vLineBuffer, 0, Math.min(vRowStride, vBuffer.remaining()));
  uBuffer.get(uLineBuffer, 0, Math.min(uRowStride, uBuffer.remaining()));
  int vLineBufferPosition = 0;
  int uLineBufferPosition = 0;
  for (int col = 0; col < chromaWidth; col++) {
  nv21[position++] = vLineBuffer[vLineBufferPosition];
  nv21[position++] = uLineBuffer[uLineBufferPosition];
  vLineBufferPosition += vPixelStride;
  uLineBufferPosition += uPixelStride;
  }
  }

  return nv21;
  }

  /** Crops JPEG byte array with given {@link android.graphics.Rect}. */
  @NonNull
  @SuppressWarnings("deprecation")
  private static byte[] cropJpegByteArray(@NonNull byte[] data, @NonNull Rect cropRect,
  @IntRange(from = 1, to = 100) int jpegQuality) throws CodecFailedException {
  Bitmap bitmap;
  try {
  BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(data, 0, data.length,
  false);
  bitmap = decoder.decodeRegion(cropRect, new BitmapFactory.Options());
  decoder.recycle();
  } catch (IllegalArgumentException e) {
  throw new CodecFailedException("Decode byte array failed with illegal argument." + e,
  CodecFailedException.FailureType.DECODE_FAILED);
  } catch (IOException e) {
  throw new CodecFailedException("Decode byte array failed.",
  CodecFailedException.FailureType.DECODE_FAILED);
  }

  if (bitmap == null) {
  throw new CodecFailedException("Decode byte array failed.",
  CodecFailedException.FailureType.DECODE_FAILED);
  }

  ByteArrayOutputStream out = new ByteArrayOutputStream();
  boolean success = bitmap.compress(Bitmap.CompressFormat.JPEG, jpegQuality, out);
  if (!success) {
  throw new CodecFailedException("Encode bitmap failed.",
  CodecFailedException.FailureType.ENCODE_FAILED);
  }
  bitmap.recycle();

  return out.toByteArray();
  }

  /** True if the given aspect ratio is meaningful. */
  public static boolean isAspectRatioValid(@Nullable Rational aspectRatio) {
  return aspectRatio != null && aspectRatio.floatValue() > 0 && !aspectRatio.isNaN();
  }

  /** True if the given aspect ratio is meaningful and has effect on the given size. */
  public static boolean isAspectRatioValid(@NonNull Size sourceSize,
  @Nullable Rational aspectRatio) {
  return aspectRatio != null
  && aspectRatio.floatValue() > 0
  && isCropAspectRatioHasEffect(sourceSize, aspectRatio)
  && !aspectRatio.isNaN();
  }

  /**
  * Calculates crop rect with the specified aspect ratio on the given size. Assuming the rect is
  * at the center of the source.
  */
  @Nullable
  public static Rect computeCropRectFromAspectRatio(@NonNull Size sourceSize,
  @NonNull Rational aspectRatio) {
  if (!isAspectRatioValid(aspectRatio)) {
  Logger.w(TAG, "Invalid view ratio.");
  return null;
  }

  int sourceWidth = sourceSize.getWidth();
  int sourceHeight = sourceSize.getHeight();
  float srcRatio = sourceWidth / (float) sourceHeight;
  int cropLeft = 0;
  int cropTop = 0;
  int outputWidth = sourceWidth;
  int outputHeight = sourceHeight;
  int numerator = aspectRatio.getNumerator();
  int denominator = aspectRatio.getDenominator();

  if (aspectRatio.floatValue() > srcRatio) {
  outputHeight = Math.round((sourceWidth / (float) numerator) * denominator);
  cropTop = (sourceHeight - outputHeight) / 2;
  } else {
  outputWidth = Math.round((sourceHeight / (float) denominator) * numerator);
  cropLeft = (sourceWidth - outputWidth) / 2;
  }

  return new Rect(cropLeft, cropTop, cropLeft + outputWidth, cropTop + outputHeight);
  }

  /**
  * Calculates crop rect based on the dispatch resolution and rotation degrees info.
  *
  * <p> The original crop rect is calculated based on camera sensor buffer. On some devices,
  * the buffer is rotated before being passed to users, in which case the crop rect also
  * needs additional transformations.
  *
  * <p> There are two most common scenarios: 1) exif rotation is 0, or 2) exif rotation
  * equals output rotation. 1) means the HAL rotated the buffer based on target
  * rotation. 2) means HAL no-oped on the rotation. Theoretically only 1) needs
  * additional transformations, but this method is also generic enough to handle all possible
  * HAL rotations.
  */
  @NonNull
  public static Rect computeCropRectFromDispatchInfo(@NonNull Rect surfaceCropRect,
  int surfaceToOutputDegrees, @NonNull Size dispatchResolution,
  int dispatchToOutputDegrees) {
  // There are 3 coordinate systems: surface, dispatch and output. Surface is where
  // the original crop rect is defined. We need to figure out what HAL
  // has done to the buffer (the surface->dispatch mapping) and apply the same
  // transformation to the crop rect.
  // The surface->dispatch mapping is calculated by inverting a dispatch->surface mapping.

  Matrix matrix = new Matrix();
  // Apply the dispatch->surface rotation.
  matrix.setRotate(dispatchToOutputDegrees - surfaceToOutputDegrees);
  // Apply the dispatch->surface translation. The translation is calculated by
  // compensating for the offset caused by the dispatch->surface rotation.
  float[] vertexes = sizeToVertexes(dispatchResolution);
  matrix.mapPoints(vertexes);
  float left = min(vertexes[0], vertexes[2], vertexes[4], vertexes[6]);
  float top = min(vertexes[1], vertexes[3], vertexes[5], vertexes[7]);
  matrix.postTranslate(-left, -top);
  // Inverting the dispatch->surface mapping to get the surface->dispatch mapping.
  matrix.invert(matrix);

  // Apply the surface->dispatch mapping to surface crop rect.
  RectF dispatchCropRectF = new RectF();
  matrix.mapRect(dispatchCropRectF, new RectF(surfaceCropRect));
  dispatchCropRectF.sort();
  Rect dispatchCropRect = new Rect();
  dispatchCropRectF.round(dispatchCropRect);
  return dispatchCropRect;
  }

  private static byte[] nv21ToJpeg(@NonNull byte[] nv21, int width, int height,
  @Nullable Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
  throws CodecFailedException {
  ByteArrayOutputStream out = new ByteArrayOutputStream();
  YuvImage yuv = new YuvImage(nv21, ImageFormat.NV21, width, height, null);
  boolean success =
  yuv.compressToJpeg(cropRect == null ? new Rect(0, 0, width, height) : cropRect,
  jpegQuality, out);
  if (!success) {
  throw new CodecFailedException("YuvImage failed to encode jpeg.",
  CodecFailedException.FailureType.ENCODE_FAILED);
  }
  return out.toByteArray();
  }

  private static boolean isCropAspectRatioHasEffect(@NonNull Size sourceSize,
  @NonNull Rational aspectRatio) {
  int sourceWidth = sourceSize.getWidth();
  int sourceHeight = sourceSize.getHeight();
  int numerator = aspectRatio.getNumerator();
  int denominator = aspectRatio.getDenominator();

  return sourceHeight != Math.round((sourceWidth / (float) numerator) * denominator)
  || sourceWidth != Math.round((sourceHeight / (float) denominator) * numerator);
  }

  private static Rational inverseRational(@Nullable Rational rational) {
  if (rational == null) {
  return rational;
  }
  return new Rational(
  /*numerator=*/ rational.getDenominator(),
  /*denominator=*/ rational.getNumerator());
  }

  /**
  * Checks whether the image's crop rectangle is the same as the source image size.
  */
  public static boolean shouldCropImage(@NonNull ImageProxy image) {
  return shouldCropImage(image.getWidth(), image.getHeight(), image.getCropRect().width(),
  image.getCropRect().height());
  }

  /**
  * Checks whether the image's crop rectangle is the same as the source image size.
  */
  public static boolean shouldCropImage(int sourceWidth, int sourceHeight, int cropRectWidth,
  int cropRectHeight) {
  return sourceWidth != cropRectWidth || sourceHeight != cropRectHeight;
  }

  /** Exception for error during transcoding image. */
  public static final class CodecFailedException extends Exception {
  public enum FailureType {
  ENCODE_FAILED,
  DECODE_FAILED,
  UNKNOWN
  }

  private FailureType mFailureType;

  CodecFailedException(@NonNull String message) {
  super(message);
  mFailureType = FailureType.UNKNOWN;
  }

  CodecFailedException(@NonNull String message, @NonNull FailureType failureType) {
  super(message);
  mFailureType = failureType;
  }

  @NonNull
  public FailureType getFailureType() {
  return mFailureType;
  }
  }
 }
	/*
	* Copyright 2020 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 androidx.camera.core.internal.utils;

	import android.graphics.Bitmap;
	import android.graphics.BitmapFactory;
	import android.graphics.BitmapRegionDecoder;
	import android.graphics.ImageFormat;
	import android.graphics.Matrix;
	import android.graphics.Rect;
	import android.graphics.RectF;
	import android.graphics.YuvImage;
	import android.util.Rational;
	import android.util.Size;

	import androidx.annotation.IntRange;
	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;
	import androidx.annotation.RequiresApi;
	import androidx.camera.core.ImageProxy;
	import androidx.camera.core.Logger;

	import java.io.ByteArrayOutputStream;
	import java.io.IOException;
	import java.nio.ByteBuffer;

	/**
	* Utility class for image related operations.
	*/
	@RequiresApi(21) // TODO(b/200306659): Remove and replace with annotation on package-info.java
	public final class ImageUtil {
	private static final String TAG = "ImageUtil";

	private ImageUtil() {
	}

	/**
	* Converts a {@link Size} to an float array of vertexes.
	*/
	@NonNull
	public static float[] sizeToVertexes(@NonNull Size size) {
	return new float[]{0, 0, size.getWidth(), 0, size.getWidth(), size.getHeight(), 0,
	size.getHeight()};
	}

	/**
	* Returns the min value.
	*/
	public static float min(float value1, float value2, float value3, float value4) {
	return Math.min(Math.min(value1, value2), Math.min(value3, value4));
	}

	/**
	* Rotates aspect ratio based on rotation degrees.
	*/
	@NonNull
	public static Rational getRotatedAspectRatio(
	@IntRange(from = 0, to = 359) int rotationDegrees,
	@NonNull Rational aspectRatio) {
	if (rotationDegrees == 90 \|\| rotationDegrees == 270) {
	return inverseRational(aspectRatio);
	}

	return new Rational(aspectRatio.getNumerator(), aspectRatio.getDenominator());
	}

	/**
	* Converts JPEG {@link ImageProxy} to JPEG byte array.
	*/
	@NonNull
	public static byte[] jpegImageToJpegByteArray(@NonNull ImageProxy image) {
	if (image.getFormat() != ImageFormat.JPEG) {
	throw new IllegalArgumentException(
	"Incorrect image format of the input image proxy: " + image.getFormat());
	}

	ImageProxy.PlaneProxy[] planes = image.getPlanes();
	ByteBuffer buffer = planes[0].getBuffer();
	byte[] data = new byte[buffer.capacity()];
	buffer.rewind();
	buffer.get(data);

	return data;
	}

	/**
	* Converts JPEG {@link ImageProxy} to JPEG byte array. The input JPEG image will be cropped
	* by the specified crop rectangle and compressed by the specified quality value.
	*/
	@NonNull
	public static byte[] jpegImageToJpegByteArray(@NonNull ImageProxy image,
	@NonNull Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
	throws CodecFailedException {
	if (image.getFormat() != ImageFormat.JPEG) {
	throw new IllegalArgumentException(
	"Incorrect image format of the input image proxy: " + image.getFormat());
	}

	byte[] data = jpegImageToJpegByteArray(image);
	data = cropJpegByteArray(data, cropRect, jpegQuality);

	return data;
	}

	/**
	* Converts YUV_420_888 {@link ImageProxy} to JPEG byte array. The input YUV_420_888 image
	* will be cropped if a non-null crop rectangle is specified. The output JPEG byte array will
	* be compressed by the specified quality value.
	*/
	@NonNull
	public static byte[] yuvImageToJpegByteArray(@NonNull ImageProxy image,
	@Nullable Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
	throws CodecFailedException {
	if (image.getFormat() != ImageFormat.YUV_420_888) {
	throw new IllegalArgumentException(
	"Incorrect image format of the input image proxy: " + image.getFormat());
	}

	return ImageUtil.nv21ToJpeg(
	ImageUtil.yuv_420_888toNv21(image),
	image.getWidth(),
	image.getHeight(),
	cropRect,
	jpegQuality);
	}

	/** {@link android.media.Image} to NV21 byte array. */
	@NonNull
	public static byte[] yuv_420_888toNv21(@NonNull ImageProxy image) {
	ImageProxy.PlaneProxy yPlane = image.getPlanes()[0];
	ImageProxy.PlaneProxy uPlane = image.getPlanes()[1];
	ImageProxy.PlaneProxy vPlane = image.getPlanes()[2];

	ByteBuffer yBuffer = yPlane.getBuffer();
	ByteBuffer uBuffer = uPlane.getBuffer();
	ByteBuffer vBuffer = vPlane.getBuffer();
	yBuffer.rewind();
	uBuffer.rewind();
	vBuffer.rewind();

	int ySize = yBuffer.remaining();

	int position = 0;
	// TODO(b/115743986): Pull these bytes from a pool instead of allocating for every image.
	byte[] nv21 = new byte[ySize + (image.getWidth() * image.getHeight() / 2)];

	// Add the full y buffer to the array. If rowStride > 1, some padding may be skipped.
	for (int row = 0; row < image.getHeight(); row++) {
	yBuffer.get(nv21, position, image.getWidth());
	position += image.getWidth();
	yBuffer.position(
	Math.min(ySize, yBuffer.position() - image.getWidth() + yPlane.getRowStride()));
	}

	int chromaHeight = image.getHeight() / 2;
	int chromaWidth = image.getWidth() / 2;
	int vRowStride = vPlane.getRowStride();
	int uRowStride = uPlane.getRowStride();
	int vPixelStride = vPlane.getPixelStride();
	int uPixelStride = uPlane.getPixelStride();

	// Interleave the u and v frames, filling up the rest of the buffer. Use two line buffers to
	// perform faster bulk gets from the byte buffers.
	byte[] vLineBuffer = new byte[vRowStride];
	byte[] uLineBuffer = new byte[uRowStride];
	for (int row = 0; row < chromaHeight; row++) {
	vBuffer.get(vLineBuffer, 0, Math.min(vRowStride, vBuffer.remaining()));
	uBuffer.get(uLineBuffer, 0, Math.min(uRowStride, uBuffer.remaining()));
	int vLineBufferPosition = 0;
	int uLineBufferPosition = 0;
	for (int col = 0; col < chromaWidth; col++) {
	nv21[position++] = vLineBuffer[vLineBufferPosition];
	nv21[position++] = uLineBuffer[uLineBufferPosition];
	vLineBufferPosition += vPixelStride;
	uLineBufferPosition += uPixelStride;
	}
	}

	return nv21;
	}

	/** Crops JPEG byte array with given {@link android.graphics.Rect}. */
	@NonNull
	@SuppressWarnings("deprecation")
	private static byte[] cropJpegByteArray(@NonNull byte[] data, @NonNull Rect cropRect,
	@IntRange(from = 1, to = 100) int jpegQuality) throws CodecFailedException {
	Bitmap bitmap;
	try {
	BitmapRegionDecoder decoder = BitmapRegionDecoder.newInstance(data, 0, data.length,
	false);
	bitmap = decoder.decodeRegion(cropRect, new BitmapFactory.Options());
	decoder.recycle();
	} catch (IllegalArgumentException e) {
	throw new CodecFailedException("Decode byte array failed with illegal argument." + e,
	CodecFailedException.FailureType.DECODE_FAILED);
	} catch (IOException e) {
	throw new CodecFailedException("Decode byte array failed.",
	CodecFailedException.FailureType.DECODE_FAILED);
	}

	if (bitmap == null) {
	throw new CodecFailedException("Decode byte array failed.",
	CodecFailedException.FailureType.DECODE_FAILED);
	}

	ByteArrayOutputStream out = new ByteArrayOutputStream();
	boolean success = bitmap.compress(Bitmap.CompressFormat.JPEG, jpegQuality, out);
	if (!success) {
	throw new CodecFailedException("Encode bitmap failed.",
	CodecFailedException.FailureType.ENCODE_FAILED);
	}
	bitmap.recycle();

	return out.toByteArray();
	}

	/** True if the given aspect ratio is meaningful. */
	public static boolean isAspectRatioValid(@Nullable Rational aspectRatio) {
	return aspectRatio != null && aspectRatio.floatValue() > 0 && !aspectRatio.isNaN();
	}

	/** True if the given aspect ratio is meaningful and has effect on the given size. */
	public static boolean isAspectRatioValid(@NonNull Size sourceSize,
	@Nullable Rational aspectRatio) {
	return aspectRatio != null
	&& aspectRatio.floatValue() > 0
	&& isCropAspectRatioHasEffect(sourceSize, aspectRatio)
	&& !aspectRatio.isNaN();
	}

	/**
	* Calculates crop rect with the specified aspect ratio on the given size. Assuming the rect is
	* at the center of the source.
	*/
	@Nullable
	public static Rect computeCropRectFromAspectRatio(@NonNull Size sourceSize,
	@NonNull Rational aspectRatio) {
	if (!isAspectRatioValid(aspectRatio)) {
	Logger.w(TAG, "Invalid view ratio.");
	return null;
	}

	int sourceWidth = sourceSize.getWidth();
	int sourceHeight = sourceSize.getHeight();
	float srcRatio = sourceWidth / (float) sourceHeight;
	int cropLeft = 0;
	int cropTop = 0;
	int outputWidth = sourceWidth;
	int outputHeight = sourceHeight;
	int numerator = aspectRatio.getNumerator();
	int denominator = aspectRatio.getDenominator();

	if (aspectRatio.floatValue() > srcRatio) {
	outputHeight = Math.round((sourceWidth / (float) numerator) * denominator);
	cropTop = (sourceHeight - outputHeight) / 2;
	} else {
	outputWidth = Math.round((sourceHeight / (float) denominator) * numerator);
	cropLeft = (sourceWidth - outputWidth) / 2;
	}

	return new Rect(cropLeft, cropTop, cropLeft + outputWidth, cropTop + outputHeight);
	}

	/**
	* Calculates crop rect based on the dispatch resolution and rotation degrees info.
	*
	* <p> The original crop rect is calculated based on camera sensor buffer. On some devices,
	* the buffer is rotated before being passed to users, in which case the crop rect also
	* needs additional transformations.
	*
	* <p> There are two most common scenarios: 1) exif rotation is 0, or 2) exif rotation
	* equals output rotation. 1) means the HAL rotated the buffer based on target
	* rotation. 2) means HAL no-oped on the rotation. Theoretically only 1) needs
	* additional transformations, but this method is also generic enough to handle all possible
	* HAL rotations.
	*/
	@NonNull
	public static Rect computeCropRectFromDispatchInfo(@NonNull Rect surfaceCropRect,
	int surfaceToOutputDegrees, @NonNull Size dispatchResolution,
	int dispatchToOutputDegrees) {
	// There are 3 coordinate systems: surface, dispatch and output. Surface is where
	// the original crop rect is defined. We need to figure out what HAL
	// has done to the buffer (the surface->dispatch mapping) and apply the same
	// transformation to the crop rect.
	// The surface->dispatch mapping is calculated by inverting a dispatch->surface mapping.

	Matrix matrix = new Matrix();
	// Apply the dispatch->surface rotation.
	matrix.setRotate(dispatchToOutputDegrees - surfaceToOutputDegrees);
	// Apply the dispatch->surface translation. The translation is calculated by
	// compensating for the offset caused by the dispatch->surface rotation.
	float[] vertexes = sizeToVertexes(dispatchResolution);
	matrix.mapPoints(vertexes);
	float left = min(vertexes[0], vertexes[2], vertexes[4], vertexes[6]);
	float top = min(vertexes[1], vertexes[3], vertexes[5], vertexes[7]);
	matrix.postTranslate(-left, -top);
	// Inverting the dispatch->surface mapping to get the surface->dispatch mapping.
	matrix.invert(matrix);

	// Apply the surface->dispatch mapping to surface crop rect.
	RectF dispatchCropRectF = new RectF();
	matrix.mapRect(dispatchCropRectF, new RectF(surfaceCropRect));
	dispatchCropRectF.sort();
	Rect dispatchCropRect = new Rect();
	dispatchCropRectF.round(dispatchCropRect);
	return dispatchCropRect;
	}

	private static byte[] nv21ToJpeg(@NonNull byte[] nv21, int width, int height,
	@Nullable Rect cropRect, @IntRange(from = 1, to = 100) int jpegQuality)
	throws CodecFailedException {
	ByteArrayOutputStream out = new ByteArrayOutputStream();
	YuvImage yuv = new YuvImage(nv21, ImageFormat.NV21, width, height, null);
	boolean success =
	yuv.compressToJpeg(cropRect == null ? new Rect(0, 0, width, height) : cropRect,
	jpegQuality, out);
	if (!success) {
	throw new CodecFailedException("YuvImage failed to encode jpeg.",
	CodecFailedException.FailureType.ENCODE_FAILED);
	}
	return out.toByteArray();
	}

	private static boolean isCropAspectRatioHasEffect(@NonNull Size sourceSize,
	@NonNull Rational aspectRatio) {
	int sourceWidth = sourceSize.getWidth();
	int sourceHeight = sourceSize.getHeight();
	int numerator = aspectRatio.getNumerator();
	int denominator = aspectRatio.getDenominator();

	return sourceHeight != Math.round((sourceWidth / (float) numerator) * denominator)
	\|\| sourceWidth != Math.round((sourceHeight / (float) denominator) * numerator);
	}

	private static Rational inverseRational(@Nullable Rational rational) {
	if (rational == null) {
	return rational;
	}
	return new Rational(
	/numerator=/ rational.getDenominator(),
	/denominator=/ rational.getNumerator());
	}

	/**
	* Checks whether the image's crop rectangle is the same as the source image size.
	*/
	public static boolean shouldCropImage(@NonNull ImageProxy image) {
	return shouldCropImage(image.getWidth(), image.getHeight(), image.getCropRect().width(),
	image.getCropRect().height());
	}

	/**
	* Checks whether the image's crop rectangle is the same as the source image size.
	*/
	public static boolean shouldCropImage(int sourceWidth, int sourceHeight, int cropRectWidth,
	int cropRectHeight) {
	return sourceWidth != cropRectWidth \|\| sourceHeight != cropRectHeight;
	}

	/** Exception for error during transcoding image. */
	public static final class CodecFailedException extends Exception {
	public enum FailureType {
	ENCODE_FAILED,
	DECODE_FAILED,
	UNKNOWN
	}

	private FailureType mFailureType;

	CodecFailedException(@NonNull String message) {
	super(message);
	mFailureType = FailureType.UNKNOWN;
	}

	CodecFailedException(@NonNull String message, @NonNull FailureType failureType) {
	super(message);
	mFailureType = failureType;
	}

	@NonNull
	public FailureType getFailureType() {
	return mFailureType;
	}
	}
	}