如何在相机预览上显示水印

Question

我正在这个项目的顶部制作运动检测器应用程序。 我想在相机预览中显示水印图像。 我尝试了这种方法，但是对我来说不起作用。 请在代码中说明如何显示水印，而运动检测部分没有任何问题。

MotionDetection.java

public class MotionDetectionActivity extends SensorsActivity {

private static final String TAG = "MotionDetectionActivity";

private static SurfaceView preview = null;
private static SurfaceHolder previewHolder = null;
private static Camera camera = null;
private static boolean inPreview = false;
private static long mReferenceTime = 0;
private static IMotionDetection detector = null;

private static volatile AtomicBoolean processing = new AtomicBoolean(false);

/**
 * {@inheritDoc}
 */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    preview = (SurfaceView) findViewById(R.id.preview);
    previewHolder = preview.getHolder();
    previewHolder.addCallback(surfaceCallback);
    previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    if (Preferences.USE_RGB) {
        detector = new RgbMotionDetection();
    } else if (Preferences.USE_LUMA) {
        detector = new LumaMotionDetection();
    } else {
        // Using State based (aggregate map)
        detector = new AggregateLumaMotionDetection();
    }
}

/**
 * {@inheritDoc}
 */
@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
}

/**
 * {@inheritDoc}
 */
@Override
public void onPause() {
    super.onPause();

    camera.setPreviewCallback(null);
    if (inPreview) camera.stopPreview();
    inPreview = false;
    camera.release();
    camera = null;
}

/**
 * {@inheritDoc}
 */
@Override
public void onResume() {
    super.onResume();

    camera = Camera.open();
}

private PreviewCallback previewCallback = new PreviewCallback() {

    /**
     * {@inheritDoc}
     */
    @Override
    public void onPreviewFrame(byte[] data, Camera cam) {
        if (data == null) return;
        Camera.Size size = cam.getParameters().getPreviewSize();
        if (size == null) return;

        if (!GlobalData.isPhoneInMotion()) {
            DetectionThread thread = new DetectionThread(data, size.width, size.height);
            thread.start();
        }
    }
};

private SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {

    /**
     * {@inheritDoc}
     */
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera.setPreviewDisplay(previewHolder);
            camera.setPreviewCallback(previewCallback);
        } catch (Throwable t) {
            Log.e("PreviewDemo-surfaceCallback", "Exception in setPreviewDisplay()", t);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Camera.Parameters parameters = camera.getParameters();
        Camera.Size size = getBestPreviewSize(width, height, parameters);
        if (size != null) {
            parameters.setPreviewSize(size.width, size.height);
            Log.d(TAG, "Using width=" + size.width + " height=" + size.height);
        }
        camera.setParameters(parameters);
        camera.startPreview();
        inPreview = true;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // Ignore
    }
};

private static Camera.Size getBestPreviewSize(int width, int height, Camera.Parameters parameters) {
    Camera.Size result = null;

    for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
        if (size.width <= width && size.height <= height) {
            if (result == null) {
                result = size;
            } else {
                int resultArea = result.width * result.height;
                int newArea = size.width * size.height;

                if (newArea > resultArea) result = size;
            }
        }
    }

    return result;
}

private static final class DetectionThread extends Thread {

    private byte[] data;
    private int width;
    private int height;

    public DetectionThread(byte[] data, int width, int height) {
        this.data = data;
        this.width = width;
        this.height = height;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void run() {
        if (!processing.compareAndSet(false, true)) return;

        // Log.d(TAG, "BEGIN PROCESSING...");
        try {
            // Previous frame
            int[] pre = null;
            if (Preferences.SAVE_PREVIOUS) pre = detector.getPrevious();

            // Current frame (with changes)
            // long bConversion = System.currentTimeMillis();
            int[] img = null;
            if (Preferences.USE_RGB) {
                img = ImageProcessing.decodeYUV420SPtoRGB(data, width, height);
            } else {
                img = ImageProcessing.decodeYUV420SPtoLuma(data, width, height);
            }
            // long aConversion = System.currentTimeMillis();
            // Log.d(TAG, "Converstion="+(aConversion-bConversion));

            // Current frame (without changes)
            int[] org = null;
            if (Preferences.SAVE_ORIGINAL && img != null) org = img.clone();

            if (img != null && detector.detect(img, width, height)) {
                // The delay is necessary to avoid taking a picture while in
                // the
                // middle of taking another. This problem can causes some
                // phones
                // to reboot.
                long now = System.currentTimeMillis();
                if (now > (mReferenceTime + Preferences.PICTURE_DELAY)) {
                    mReferenceTime = now;

                    Bitmap previous = null;
                    if (Preferences.SAVE_PREVIOUS && pre != null) {
                        if (Preferences.USE_RGB) previous = ImageProcessing.rgbToBitmap(pre, width, height);
                        else previous = ImageProcessing.lumaToGreyscale(pre, width, height);
                    }

                    Bitmap original = null;
                    if (Preferences.SAVE_ORIGINAL && org != null) {
                        if (Preferences.USE_RGB) original = ImageProcessing.rgbToBitmap(org, width, height);
                        else original = ImageProcessing.lumaToGreyscale(org, width, height);
                    }

                    Bitmap bitmap = null;
                    if (Preferences.SAVE_CHANGES) {
                        if (Preferences.USE_RGB) bitmap = ImageProcessing.rgbToBitmap(img, width, height);
                        else bitmap = ImageProcessing.lumaToGreyscale(img, width, height);
                    }

                    Log.i(TAG, "Saving.. previous=" + previous + " original=" + original + " bitmap=" + bitmap);
                    Looper.prepare();
                    new SavePhotoTask().execute(previous, original, bitmap);
                } else {
                    Log.i(TAG, "Not taking picture because not enough time has passed since the creation of the Surface");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            processing.set(false);
        }
        // Log.d(TAG, "END PROCESSING...");

        processing.set(false);
    }
};

private static final class SavePhotoTask extends AsyncTask<Bitmap, Integer, Integer> {

    /**
     * {@inheritDoc}
     */
    @Override
    protected Integer doInBackground(Bitmap... data) {
        for (int i = 0; i < data.length; i++) {
            Bitmap bitmap = data[i];
            String name = String.valueOf(System.currentTimeMillis());
            if (bitmap != null) save(name, bitmap);
        }
        return 1;
    }

    private void save(String name, Bitmap bitmap) {
        File photo = new File(Environment.getExternalStorageDirectory(), name + ".jpg");
        if (photo.exists()) photo.delete();

        try {
            FileOutputStream fos = new FileOutputStream(photo.getPath());
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
            fos.close();
        } catch (java.io.IOException e) {
            Log.e("PictureDemo", "Exception in photoCallback", e);
        }
    }
}
}

main.xml中

<?xml version="1.0" encoding="utf-8"?>
<SurfaceView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</SurfaceView>

Answer 1

解决方法是将活动XML文件与另一个包含水印图像的XML文件重叠。 为此：

1. 在布局文件夹中创建一个新的布局文件。 例如： overlay.xml

2. 在其中插入一个ImageView ，类似：

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" xmlns:app="http://schemas.android.com/apk/res-auto"> <ImageView android:id="@+id/imageView1" android:layout_centerInParent="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android" /> </RelativeLayout> 

3. 然后在Activity java文件（即MotionDetector.java文件）中，创建一个新方法addView() ：

     private void addView() { controlInflater = LayoutInflater.from(getBaseContext()); View viewControl = controlInflater.inflate(R.layout.overlay, null); LayoutParams layoutParamsControl = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); this.addContentView(viewControl, layoutParamsControl); } 

4）最后从onCreate()调用addView()方法添加图像：

super.onCreate(savedInstanceState);
setContentView(R.layout.main);

preview = (SurfaceView) findViewById(R.id.preview);
previewHolder = preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
addView();

然后最终结果将是在SurfaceView上方覆盖图像。 视水印图像的质量而定，水印的渲染质量应看起来像是原始的。 希望能帮助到你。