com.team254.cheezdroid.SelfieModeFragment.java Source code

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/*
 * 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 com.team254.cheezdroid;

import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;
import android.graphics.YuvImage;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.CaptureResult;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.media.Image;
import android.media.ImageReader;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.support.annotation.NonNull;
import android.support.v13.app.FragmentCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.LayoutInflater;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

public class SelfieModeFragment extends Fragment
        implements View.OnClickListener, FragmentCompat.OnRequestPermissionsResultCallback {

    /**
     * Conversion from screen rotation to JPEG orientation.
     */
    private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
    private static final int REQUEST_CAMERA_PERMISSION = 1;
    private static final String FRAGMENT_DIALOG = "dialog";

    static {
        ORIENTATIONS.append(Surface.ROTATION_0, 90);
        ORIENTATIONS.append(Surface.ROTATION_90, 0);
        ORIENTATIONS.append(Surface.ROTATION_180, 270);
        ORIENTATIONS.append(Surface.ROTATION_270, 180);
    }

    /**
     * Tag for the {@link Log}.
     */
    private static final String TAG = "SelfieModeFragment";

    /**
     * Camera state: Showing camera preview.
     */
    private static final int STATE_PREVIEW = 0;

    /**
     * Camera state: Waiting for the focus to be locked.
     */
    private static final int STATE_WAITING_LOCK = 1;

    /**
     * Camera state: Waiting for the exposure to be precapture state.
     */
    private static final int STATE_WAITING_PRECAPTURE = 2;

    /**
     * Camera state: Waiting for the exposure state to be something other than precapture.
     */
    private static final int STATE_WAITING_NON_PRECAPTURE = 3;

    /**
     * Camera state: Picture was taken.
     */
    private static final int STATE_PICTURE_TAKEN = 4;

    /**
     * Max preview width that is guaranteed by Camera2 API
     */
    private static final int MAX_PREVIEW_WIDTH = 352;

    /**
     * Max preview height that is guaranteed by Camera2 API
     */
    private static final int MAX_PREVIEW_HEIGHT = 1080;

    /**
     * {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a
     * {@link TextureView}.
     */
    private final TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() {

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) {
            openCamera(width, height);
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) {
            configureTransform(width, height);
        }

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) {
            return true;
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture texture) {
        }

    };

    /**
     * ID of the current {@link CameraDevice}.
     */
    private String mCameraId;

    /**
     * An {@link AutoFitTextureView} for camera preview.
     */
    private AutoFitTextureView mTextureView;

    /**
     * A {@link CameraCaptureSession } for camera preview.
     */
    private CameraCaptureSession mCaptureSession;

    /**
     * A reference to the opened {@link CameraDevice}.
     */
    private CameraDevice mCameraDevice;

    /**
     * The {@link android.util.Size} of camera preview.
     */
    private Size mPreviewSize;

    /**
     * {@link CameraDevice.StateCallback} is called when {@link CameraDevice} changes its state.
     */
    private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

        @Override
        public void onOpened(@NonNull CameraDevice cameraDevice) {
            // This method is called when the camera is opened.  We start camera preview here.
            mCameraOpenCloseLock.release();
            mCameraDevice = cameraDevice;
            createCameraPreviewSession();
        }

        @Override
        public void onDisconnected(@NonNull CameraDevice cameraDevice) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
        }

        @Override
        public void onError(@NonNull CameraDevice cameraDevice, int error) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
            Activity activity = getActivity();
            if (null != activity) {
                activity.finish();
            }
        }

    };

    /**
     * An additional thread for running tasks that shouldn't block the UI.
     */
    private HandlerThread mBackgroundThread;

    /**
     * A {@link Handler} for running tasks in the background.
     */
    private Handler mBackgroundHandler;

    /**
     * An {@link ImageReader} that handles still image capture.
     */
    private ImageReader mImageReader;

    /**
     * This is the output file for our picture.
     */
    private File mFile;

    /**
     * This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a
     * still image is ready to be saved.
     */

    private byte[] convertYUV420ToN21(Image imgYUV420) {
        byte[] rez = new byte[0];

        ByteBuffer buffer0 = imgYUV420.getPlanes()[0].getBuffer();
        ByteBuffer buffer2 = imgYUV420.getPlanes()[2].getBuffer();
        int buffer0_size = buffer0.remaining();
        int buffer2_size = buffer2.remaining();
        rez = new byte[buffer0_size + buffer2_size];

        buffer0.get(rez, 0, buffer0_size);
        buffer2.get(rez, buffer0_size, buffer2_size);

        return rez;
    }

    public class ImageStreamer implements Runnable {

        private Image i;
        private long t = System.currentTimeMillis();

        public ImageStreamer(Image i) {
            this.i = i;
        }

        @Override
        public void run() {
            long now = System.currentTimeMillis();
            int width = i.getWidth();
            int height = i.getHeight();
            byte[] n21ImageData = convertYUV420ToN21(i);
            i.close();
            YuvImage yuvImage = new YuvImage(n21ImageData, ImageFormat.NV21, width, height, null);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int quality = 20; //set quality
            yuvImage.compressToJpeg(new Rect(0, 0, width, height), quality, baos);
            byte[] jpgBytes = baos.toByteArray();
            //MjpgServer.getInstance().update(jpgBytes);
            t = now;
        }
    }

    private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {

        @Override
        public void onImageAvailable(ImageReader reader) {
            mBackgroundHandler.post(new ImageStreamer(reader.acquireNextImage()));
        }

    };

    /**
     * {@link CaptureRequest.Builder} for the camera preview
     */
    private CaptureRequest.Builder mPreviewRequestBuilder;

    /**
     * {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder}
     */
    private CaptureRequest mPreviewRequest;

    /**
     * The current state of camera state for taking pictures.
     *
     * @see #mCaptureCallback
     */
    private int mState = STATE_PREVIEW;

    /**
     * A {@link Semaphore} to prevent the app from exiting before closing the camera.
     */
    private Semaphore mCameraOpenCloseLock = new Semaphore(1);

    /**
     * Whether the current camera device supports Flash or not.
     */
    private boolean mFlashSupported;

    /**
     * A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture.
     */
    private CameraCaptureSession.CaptureCallback mCaptureCallback = new CameraCaptureSession.CaptureCallback() {

        private void process(CaptureResult result) {

        }

        @Override
        public void onCaptureProgressed(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request,
                @NonNull CaptureResult partialResult) {
            process(partialResult);
        }

        @Override
        public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request,
                @NonNull TotalCaptureResult result) {
            process(result);
        }

    };

    /**
     * Shows a {@link Toast} on the UI thread.
     *
     * @param text The message to show
     */
    private void showToast(final String text) {
        final Activity activity = getActivity();
        if (activity != null) {
            activity.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(activity, text, Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

    /**
     * Given {@code choices} of {@code Size}s supported by a camera, choose the smallest one that
     * is at least as large as the respective texture view size, and that is at most as large as the
     * respective max size, and whose aspect ratio matches with the specified value. If such size
     * doesn't exist, choose the largest one that is at most as large as the respective max size,
     * and whose aspect ratio matches with the specified value.
     *
     * @param choices           The list of sizes that the camera supports for the intended output
     *                          class
     * @param textureViewWidth  The width of the texture view relative to sensor coordinate
     * @param textureViewHeight The height of the texture view relative to sensor coordinate
     * @param maxWidth          The maximum width that can be chosen
     * @param maxHeight         The maximum height that can be chosen
     * @param aspectRatio       The aspect ratio
     * @return The optimal {@code Size}, or an arbitrary one if none were big enough
     */
    private static Size chooseOptimalSize(Size[] choices, int textureViewWidth, int textureViewHeight, int maxWidth,
            int maxHeight, Size aspectRatio) {

        // Collect the supported resolutions that are at least as big as the preview Surface
        List<Size> bigEnough = new ArrayList<>();
        // Collect the supported resolutions that are smaller than the preview Surface
        List<Size> notBigEnough = new ArrayList<>();
        int w = aspectRatio.getWidth();
        int h = aspectRatio.getHeight();
        for (Size option : choices) {
            if (option.getWidth() <= maxWidth && option.getHeight() <= maxHeight
                    && option.getHeight() == option.getWidth() * h / w) {
                if (option.getWidth() >= textureViewWidth && option.getHeight() >= textureViewHeight) {
                    bigEnough.add(option);
                } else {
                    notBigEnough.add(option);
                }
            }
        }

        // Pick the smallest of those big enough. If there is no one big enough, pick the
        // largest of those not big enough.
        if (bigEnough.size() > 0) {
            return Collections.min(bigEnough, new CompareSizesByArea());
        } else if (notBigEnough.size() > 0) {
            return Collections.max(notBigEnough, new CompareSizesByArea());
        } else {
            Log.e(TAG, "Couldn't find any suitable preview size");
            return choices[0];
        }
    }

    public static SelfieModeFragment newInstance() {
        return new SelfieModeFragment();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_camera2_basic, container, false);
    }

    @Override
    public void onViewCreated(final View view, Bundle savedInstanceState) {
        mTextureView = (AutoFitTextureView) view.findViewById(R.id.texture);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mFile = new File(getActivity().getExternalFilesDir(null), "pic.jpg");
    }

    @Override
    public void onResume() {
        super.onResume();
        startBackgroundThread();

        // When the screen is turned off and turned back on, the SurfaceTexture is already
        // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
        // a camera and start preview from here (otherwise, we wait until the surface is ready in
        // the SurfaceTextureListener).
        if (mTextureView.isAvailable()) {
            openCamera(mTextureView.getWidth(), mTextureView.getHeight());
        } else {
            mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
        }
    }

    @Override
    public void onPause() {
        closeCamera();
        stopBackgroundThread();
        super.onPause();
    }

    private void requestCameraPermission() {
        if (FragmentCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
            new ConfirmationDialog().show(getChildFragmentManager(), FRAGMENT_DIALOG);
        } else {
            FragmentCompat.requestPermissions(this, new String[] { Manifest.permission.CAMERA },
                    REQUEST_CAMERA_PERMISSION);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
            @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults.length != 1 || grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                ErrorDialog.newInstance(getString(R.string.request_permission)).show(getChildFragmentManager(),
                        FRAGMENT_DIALOG);
            }
        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    /**
     * Sets up member variables related to camera.
     *
     * @param width  The width of available size for camera preview
     * @param height The height of available size for camera preview
     */
    private void setUpCameraOutputs(int width, int height) {
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            for (String cameraId : manager.getCameraIdList()) {
                Log.i("CameraId", cameraId);
                CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);

                // We don't use a front facing camera in this sample.
                Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
                if (facing != null && facing == CameraCharacteristics.LENS_FACING_BACK) {
                    Log.w(TAG, "Skipped for facing " + cameraId);
                    continue;
                }

                StreamConfigurationMap map = characteristics
                        .get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
                if (map == null) {
                    Log.w(TAG, "Skipped for null map " + cameraId);
                    continue;
                }

                // For still image captures, we use the largest available size.
                Size[] imgSizes = map.getOutputSizes(ImageFormat.YUV_420_888);
                Size selected = imgSizes[imgSizes.length - 1];
                for (Size s : imgSizes) {
                    if (s.getWidth() <= 352) {
                        selected = s;
                        break;
                    }
                }
                mImageReader = ImageReader.newInstance(selected.getWidth(), selected.getHeight(),
                        ImageFormat.YUV_420_888, /*maxImages*/3);
                mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, mBackgroundHandler);

                // Find out if we need to swap dimension to get the preview size relative to sensor
                // coordinate.
                int displayRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
                int sensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
                boolean swappedDimensions = false;
                switch (displayRotation) {
                case Surface.ROTATION_0:
                case Surface.ROTATION_180:
                    if (sensorOrientation == 90 || sensorOrientation == 270) {
                        swappedDimensions = true;
                    }
                    break;
                case Surface.ROTATION_90:
                case Surface.ROTATION_270:
                    if (sensorOrientation == 0 || sensorOrientation == 180) {
                        swappedDimensions = true;
                    }
                    break;
                default:
                    Log.e(TAG, "Display rotation is invalid: " + displayRotation);
                }

                Point displaySize = new Point();
                activity.getWindowManager().getDefaultDisplay().getSize(displaySize);
                int rotatedPreviewWidth = width;
                int rotatedPreviewHeight = height;
                int maxPreviewWidth = displaySize.x;
                int maxPreviewHeight = displaySize.y;

                if (swappedDimensions) {
                    rotatedPreviewWidth = height;
                    rotatedPreviewHeight = width;
                    maxPreviewWidth = displaySize.y;
                    maxPreviewHeight = displaySize.x;
                }

                if (maxPreviewWidth > MAX_PREVIEW_WIDTH) {
                    maxPreviewWidth = MAX_PREVIEW_WIDTH;
                }

                if (maxPreviewHeight > MAX_PREVIEW_HEIGHT) {
                    maxPreviewHeight = MAX_PREVIEW_HEIGHT;
                }

                // Danger, W.R.! Attempting to use too large a preview size could  exceed the camera
                // bus' bandwidth limitation, resulting in gorgeous previews but the storage of
                // garbage capture data.
                mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), rotatedPreviewWidth,
                        rotatedPreviewHeight, maxPreviewWidth, maxPreviewHeight, selected);

                Log.i(TAG, "Size : " + mPreviewSize);

                // We fit the aspect ratio of TextureView to the size of preview we picked.
                int orientation = getResources().getConfiguration().orientation;
                if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
                    mTextureView.setAspectRatio(mPreviewSize.getWidth(), mPreviewSize.getHeight());
                } else {
                    mTextureView.setAspectRatio(mPreviewSize.getHeight(), mPreviewSize.getWidth());
                }

                // Check if the flash is supported.
                Boolean available = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
                mFlashSupported = available == null ? false : available;

                mCameraId = cameraId;
                return;
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            e.printStackTrace();
            // Currently an NPE is thrown when the Camera2API is used but not supported on the
            // device this code runs.
            ErrorDialog.newInstance("Camera error").show(getChildFragmentManager(), FRAGMENT_DIALOG);
        }
    }

    /**
     * Opens the camera specified by {@link SelfieModeFragment#mCameraId}.
     */
    private void openCamera(int width, int height) {
        if (ContextCompat.checkSelfPermission(getActivity(),
                Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            requestCameraPermission();
            return;
        }
        setUpCameraOutputs(width, height);
        configureTransform(width, height);
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
                throw new RuntimeException("Time out waiting to lock camera opening.");
            }
            manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
        }
    }

    /**
     * Closes the current {@link CameraDevice}.
     */
    private void closeCamera() {
        try {
            mCameraOpenCloseLock.acquire();
            if (null != mCaptureSession) {
                mCaptureSession.close();
                mCaptureSession = null;
            }
            if (null != mCameraDevice) {
                mCameraDevice.close();
                mCameraDevice = null;
            }
            if (null != mImageReader) {
                mImageReader.close();
                mImageReader = null;
            }
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera closing.", e);
        } finally {
            mCameraOpenCloseLock.release();
        }
    }

    /**
     * Starts a background thread and its {@link Handler}.
     */
    private void startBackgroundThread() {
        mBackgroundThread = new HandlerThread("CameraBackground");
        mBackgroundThread.start();
        mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
    }

    /**
     * Stops the background thread and its {@link Handler}.
     */
    private void stopBackgroundThread() {
        mBackgroundThread.quitSafely();
        try {
            mBackgroundThread.join();
            mBackgroundThread = null;
            mBackgroundHandler = null;
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    /**
     * Creates a new {@link CameraCaptureSession} for camera preview.
     */
    private void createCameraPreviewSession() {
        try {
            SurfaceTexture texture = mTextureView.getSurfaceTexture();
            assert texture != null;

            // We configure the size of default buffer to be the size of camera preview we want.
            texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());

            // This is the output Surface we need to start preview.
            Surface surface = new Surface(texture);

            // We set up a CaptureRequest.Builder with the output Surface.
            mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            mPreviewRequestBuilder.addTarget(mImageReader.getSurface());
            mPreviewRequestBuilder.addTarget(surface);

            // Here, we create a CameraCaptureSession for camera preview.
            mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
                    new CameraCaptureSession.StateCallback() {

                        @Override
                        public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                            // The camera is already closed
                            if (null == mCameraDevice) {
                                return;
                            }

                            // When the session is ready, we start displaying the preview.
                            mCaptureSession = cameraCaptureSession;
                            try {
                                // Auto focus should be continuous for camera preview.
                                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
                                        CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);

                                // Finally, we start displaying the camera preview.
                                mPreviewRequest = mPreviewRequestBuilder.build();
                                mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback,
                                        mBackgroundHandler);
                            } catch (CameraAccessException e) {
                                e.printStackTrace();
                            }
                        }

                        @Override
                        public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                            showToast("Failed");
                        }
                    }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Configures the necessary {@link android.graphics.Matrix} transformation to `mTextureView`.
     * This method should be called after the camera preview size is determined in
     * setUpCameraOutputs and also the size of `mTextureView` is fixed.
     *
     * @param viewWidth  The width of `mTextureView`
     * @param viewHeight The height of `mTextureView`
     */
    private void configureTransform(int viewWidth, int viewHeight) {
        Activity activity = getActivity();
        if (null == mTextureView || null == mPreviewSize || null == activity) {
            return;
        }
        int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
        Matrix matrix = new Matrix();
        RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
        RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
        float centerX = viewRect.centerX();
        float centerY = viewRect.centerY();
        if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
            float scale = Math.max((float) viewHeight / mPreviewSize.getHeight(),
                    (float) viewWidth / mPreviewSize.getWidth());
            matrix.postScale(scale, scale, centerX, centerY);
            matrix.postRotate(90 * (rotation - 2), centerX, centerY);
        } else if (Surface.ROTATION_180 == rotation) {
            matrix.postRotate(180, centerX, centerY);
        }
        mTextureView.setTransform(matrix);
    }

    /**
     * Initiate a still image capture.
     */
    private void takePicture() {
        lockFocus();
    }

    /**
     * Lock the focus as the first step for a still image capture.
     */
    private void lockFocus() {
        try {
            // This is how to tell the camera to lock focus.
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
            // Tell #mCaptureCallback to wait for the lock.
            mState = STATE_WAITING_LOCK;
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Run the precapture sequence for capturing a still image. This method should be called when
     * we get a response in {@link #mCaptureCallback} from {@link #lockFocus()}.
     */
    private void runPrecaptureSequence() {
        try {
            // This is how to tell the camera to trigger.
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
                    CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
            // Tell #mCaptureCallback to wait for the precapture sequence to be set.
            mState = STATE_WAITING_PRECAPTURE;
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onClick(View v) {

    }

    /**
     * Compares two {@code Size}s based on their areas.
     */
    static class CompareSizesByArea implements Comparator<Size> {

        @Override
        public int compare(Size lhs, Size rhs) {
            // We cast here to ensure the multiplications won't overflow
            return Long.signum((long) lhs.getWidth() * lhs.getHeight() - (long) rhs.getWidth() * rhs.getHeight());
        }

    }

    /**
     * Shows an error message dialog.
     */
    public static class ErrorDialog extends DialogFragment {

        private static final String ARG_MESSAGE = "message";

        public static ErrorDialog newInstance(String message) {
            ErrorDialog dialog = new ErrorDialog();
            Bundle args = new Bundle();
            args.putString(ARG_MESSAGE, message);
            dialog.setArguments(args);
            return dialog;
        }

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Activity activity = getActivity();
            return new AlertDialog.Builder(activity).setMessage(getArguments().getString(ARG_MESSAGE))
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            activity.finish();
                        }
                    }).create();
        }

    }

    /**
     * Shows OK/Cancel confirmation dialog about camera permission.
     */
    public static class ConfirmationDialog extends DialogFragment {

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Fragment parent = getParentFragment();
            return new AlertDialog.Builder(getActivity()).setMessage(R.string.request_permission)
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            FragmentCompat.requestPermissions(parent, new String[] { Manifest.permission.CAMERA },
                                    REQUEST_CAMERA_PERMISSION);
                        }
                    }).setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Activity activity = parent.getActivity();
                            if (activity != null) {
                                activity.finish();
                            }
                        }
                    }).create();
        }
    }

}