camera2 api 图像上的水印

Question

我在我的 android 应用程序中使用 camera2 API 我想在图像上制作一些 png 水印，如果可能的话请帮助我提前谢谢你。换句话说，我想在拍摄的照片上制作 png 水印，这可能吗？在我看来，camera2 API 必须有一些方法来制作它，但我还没有安排在互联网上找到一些东西没有很多文档，所以我希望你知道一些关于它的东西。

 private void takePicture() {
        if(cameraDevice == null)
            return;
        CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
        try{
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
            Size[] jpegSizes = null;
            if(characteristics != null)
                jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)
                        .getOutputSizes(ImageFormat.JPEG);

            //Capture image with custom size
            int width = 1000;
            int height = 1000;
            /*
            if(jpegSizes != null && jpegSizes.length > 0)
            {
                width = jpegSizes[0].getWidth();
                height = jpegSizes[0].getHeight();
            }
            */
            final ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,1);
            List<Surface> outputSurface = new ArrayList<>(2);
            outputSurface.add(reader.getSurface());
            outputSurface.add(new Surface(textureView.getSurfaceTexture()));

            final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
            captureBuilder.addTarget(reader.getSurface());
            captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);

            //Check orientation base on device
            int rotation = getWindowManager().getDefaultDisplay().getRotation();
            captureBuilder.set(CaptureRequest.JPEG_ORIENTATION,ORIENTATIONS.get(rotation));

            file = new File(Environment.getExternalStorageDirectory()+"/"+UUID.randomUUID().toString()+".jpg");
            ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
                @Override
                public void onImageAvailable(ImageReader imageReader) {
                    Image image = null;
                    try{
                        image = reader.acquireLatestImage();
                        ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                        byte[] bytes = new byte[buffer.capacity()];
                        buffer.get(bytes);
                        save(bytes);

                    }
                    catch (FileNotFoundException e)
                    {
                        e.printStackTrace();
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }
                    finally {
                        {
                            if(image != null)
                                image.close();
                        }
                    }
                }
                private void save(byte[] bytes) throws IOException {
                    OutputStream outputStream = null;
                    try{
                        outputStream = new FileOutputStream(file);
                        outputStream.write(bytes);
                    }finally {
                        if(outputStream != null)
                            outputStream.close();
                    }
                }
            };

            reader.setOnImageAvailableListener(readerListener,mBackgroundHandler);
            final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
                @Override
                public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
                    super.onCaptureCompleted(session, request, result);
                    Toast.makeText(MainActivity.this, "Saved "+file, Toast.LENGTH_SHORT).show();
                    createCameraPreview();
                }
            };

            cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                    try{
                        cameraCaptureSession.capture(captureBuilder.build(),captureListener,mBackgroundHandler);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }
                }

                @Override
                public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

                }
            },mBackgroundHandler);


        } catch (CameraAccessException e) {
            e.printStackTrace();
        }

    }

Answer 1

自定义图像处理与任何相机无关API，因此没有应用任何类型水印的方法。

解决方法是将照片加载为位图，通过用位图初始化的canvas渲染水印，然后再次保存。

您需要考虑的一些注意事项：

如果加载大图。 Here 避免任何问题的一些提示。
如果再次保存为 JPEG，您可能需要复制原始 EXIF 新修改图像的详细信息。
您应该在后台线程中执行所有这些操作以避免阻塞 UI，因为该操作肯定会耗费时间。

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