android - 保存图像时，图像会旋转 90 度。使用 CameraX

Question

  private void startCamera() {

        CameraX.unbindAll();

        Rational aspectRatio = new Rational (textureView.getWidth(), textureView.getHeight());
        Size screen = new Size(textureView.getWidth(), textureView.getHeight()); //size of the screen


        PreviewConfig pConfig = new PreviewConfig.Builder()
                                    .setTargetAspectRatio(aspectRatio)
                                    .setTargetResolution(screen)
                                    .setLensFacing(CameraX.LensFacing.BACK)
                                    .build();
        Preview preview = new Preview(pConfig);

        preview.setOnPreviewOutputUpdateListener(
                new Preview.OnPreviewOutputUpdateListener() {
                    @Override
                    public void onUpdated(Preview.PreviewOutput output){
                        ViewGroup parent = (ViewGroup) textureView.getParent();
                        parent.removeView(textureView);
                        parent.addView(textureView, 0);

                        textureView.setSurfaceTexture(output.getSurfaceTexture());

                        int a=output.getRotationDegrees();
                        Log.d( TAG , "output Rota3: " + String.valueOf( a) );

                        updateTransform();
                    }
                });
        ImageCaptureConfig imageCaptureConfig = new ImageCaptureConfig.Builder().setCaptureMode(ImageCapture.CaptureMode.MIN_LATENCY)
                .setTargetRotation((getWindowManager().getDefaultDisplay().getRotation())).setFlashMode( FlashMode.OFF ).build();
              imgCap = new ImageCapture(imageCaptureConfig);

        imgCapture.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
              File file = new File(Environment.getExternalStorageDirectory() + "/" + "IMG_" +System.currentTimeMillis() + ".png");
                imgCap.takePicture(file, new ImageCapture.OnImageSavedListener() {

                    @Override
                    public void onImageSaved(@NonNull File file) {
                        String msg = "Pic captured at " + file.getAbsolutePath();
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onError(@NonNull ImageCapture.UseCaseError useCaseError, @NonNull String message, @Nullable Throwable cause) {
                        String msg = "Pic capture failed : " + message;
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                        if(cause != null){
                            cause.printStackTrace();
                        }
                    }
                });
            }
        });
        CameraX.bindToLifecycle((LifecycleOwner)this, preview, imgCap);
    }

    private void updateTransform(){
        Matrix mx = new Matrix();
        float w = textureView.getMeasuredWidth();
        float h = textureView.getMeasuredHeight();

        float cX = w / 2f;
        float cY = h / 2f;

        int rotationDgr;
        int rotation = (int)textureView.getRotation();
        Log.d( TAG , "rotation: " + rotation );

        switch(rotation){
            case Surface.ROTATION_0:
                rotationDgr = 0;
                break;
            case Surface.ROTATION_90:
                rotationDgr = 90;
                break;
            case Surface.ROTATION_180:
                rotationDgr = 180;
                break;
            case Surface.ROTATION_270:
                rotationDgr = 270;
                break;
            default:
                return;
        }

        Log.d( TAG , "rotationDGR: " + rotationDgr );
        mx.postRotate((float)rotationDgr, cX, cY);
        textureView.setTransform(mx);
    }

1. 使用过 CameraX。 正在开发应用程序来捕获图像并在捕获后将其保存。 但不幸的是，我总是在每个设备中将方向 0 作为获取 TargetRotaion() 的值。即使在 90 度旋转的图像设备中也是如此。

2. 问题是图像在保存时会旋转。 我尝试了 StackOverflow 上建议的一些解决方案，但无法解决问题。

Answer 1

使用这个类` 公共(public)类 DeviceOrientation {

private static final String TAG = "CameraExif";

// Returns the degrees in clockwise. Values are 0, 90, 180, or 270.
public static int getOrientation(byte[] jpeg) {
    if (jpeg == null) {
        return 0;
    }

    int offset = 0;
    int length = 0;

    // ISO/IEC 10918-1:1993(E)
    while (offset + 3 < jpeg.length && (jpeg[offset++] & 0xFF) == 0xFF) {
        int marker = jpeg[offset] & 0xFF;

        // Check if the marker is a padding.
        if (marker == 0xFF) {
            continue;
        }
        offset++;

        // Check if the marker is SOI or TEM.
        if (marker == 0xD8 || marker == 0x01) {
            continue;
        }
        // Check if the marker is EOI or SOS.
        if (marker == 0xD9 || marker == 0xDA) {
            break;
        }

        // Get the length and check if it is reasonable.
        length = pack(jpeg, offset, 2, false);
        if (length < 2 || offset + length > jpeg.length) {
            Log.e(TAG, "Invalid length");
            return 0;
        }

        // Break if the marker is EXIF in APP1.
        if (marker == 0xE1 && length >= 8 &&
                pack(jpeg, offset + 2, 4, false) == 0x45786966 &&
                pack(jpeg, offset + 6, 2, false) == 0) {
            offset += 8;
            length -= 8;
            break;
        }

        // Skip other markers.
        offset += length;
        length = 0;
    }

    // JEITA CP-3451 DeviceOrientation Version 2.2
    if (length > 8) {
        // Identify the byte order.
        int tag = pack(jpeg, offset, 4, false);
        if (tag != 0x49492A00 && tag != 0x4D4D002A) {
            Log.e(TAG, "Invalid byte order");
            return 0;
        }
        boolean littleEndian = (tag == 0x49492A00);

        // Get the offset and check if it is reasonable.
        int count = pack(jpeg, offset + 4, 4, littleEndian) + 2;
        if (count < 10 || count > length) {
            Log.e(TAG, "Invalid offset");
            return 0;
        }
        offset += count;
        length -= count;

        // Get the count and go through all the elements.
        count = pack(jpeg, offset - 2, 2, littleEndian);
        while (count-- > 0 && length >= 12) {
            // Get the tag and check if it is orientation.
            tag = pack(jpeg, offset, 2, littleEndian);
            if (tag == 0x0112) {
                // We do not really care about type and count, do we?
                int orientation = pack(jpeg, offset + 8, 2, littleEndian);
                switch (orientation) {
                    case 1:
                        return 0;
                    case 3:
                        return 180;
                    case 6:
                        return 90;
                    case 8:
                        return 270;
                }
                Log.i(TAG, "Unsupported orientation");
                return 0;
            }
            offset += 12;
            length -= 12;
        }
    }

    Log.i(TAG, "Orientation not found");
    return 0;
}

private static int pack(byte[] bytes, int offset, int length,
                        boolean littleEndian) {
    int step = 1;
    if (littleEndian) {
        offset += length - 1;
        step = -1;
    }
    int value = 0;
    while (length-- > 0) {
        value = (value << 8) | (bytes[offset] & 0xFF);
        offset += step;
    }
    return value;
}

}`

拍照后使用此方法

  int orientation = DeviceOrientation.getOrientation(bytes);