Android拍摄照片、视频添加水印功能

最近项目中需要实现拍摄照片、视频添加水印的需求，在网上找了一圈都没找到特别好用的三方，于是自己借鉴其他库实现了一个拍摄照片及视频添加水印的功能，本项目中的水印均以图片的形式添加进去！！！

先看下效果图吧（GIF图片一直上传不上去，只能演示下静态图片，动态图片可以上Github查看）

实现原理也很简单，图片水印就是将拍摄的照片转成bitmap，然后将水印内容以图片或者文字的形式绘制到一起去，视频水印通过RxFFmpeg库来实现的，该库实现的方式不是拍摄实时添加水印，而是视频拍摄好后，提供水印图片合成到视频中去的方式实现。

核心代码

  /**
   * 绘制图片水印
   */
    public void stampImage(Bitmap masterBitmap, Bitmap watermark, StampPadding padding, int requestId) {

        int width = masterBitmap.getWidth();
        int height = masterBitmap.getHeight();

        Paint paint = new Paint();
        paint.setFilterBitmap(true);

        Bitmap newBitmap = null;
        Canvas canvas = null;

        try {
            newBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);

            canvas = new Canvas(newBitmap);
            canvas.drawBitmap(masterBitmap, 0, 0, paint);

            canvas.drawBitmap(watermark, padding.left, padding.top-watermark.getHeight(), paint);

            canvas.save();
            canvas.restore();

            if (mStampWatcher != null) {
                mStampWatcher.onSuccess(newBitmap,requestId);
            }
        } catch (Exception e) {

            if (mStampWatcher != null) {
                mStampWatcher.onError(e.getMessage(),requestId);
            }
        }
    }

 /**
   * 绘制文字水印
   */
    public void stampText(Bitmap masterBitmap, String label, int labelSize, int labelColor, StampPadding padding, int requestId) {
        Paint paint = new Paint();
        paint.setFilterBitmap(true);
        paint.setDither(true);
        paint.setColor(labelColor);
        paint.setTextSize(labelSize);

        Bitmap newBitmap = null;
        Canvas canvas = null;
        try {
            Bitmap.Config config = masterBitmap.getConfig();
            if (config == null) {
                config = Bitmap.Config.ARGB_8888;
            }
            newBitmap = masterBitmap.copy(config, true);
            canvas = new Canvas(newBitmap);
            canvas.drawText(label, padding.left, padding.top, paint);
//            canvas.save(Canvas.ALL_SAVE_FLAG); 在androidP上会报错，修改为canvas.save()
            canvas.save();
            canvas.restore();
            if (mStampWatcher != null) {
                mStampWatcher.onSuccess(newBitmap,requestId);
            }
        } catch (Exception e) {

            if (mStampWatcher != null) {
                mStampWatcher.onError(e.getMessage(),requestId);
            }
        }
    }

    /**
     * 添加视频水印
     * rxjava方式调用
     */
    private void runFFmpegRxJava() {
        openProgressDialog();
        //下面text中有三个本地地址，第一个地址为视频原文件地址，第二个地址为图片水印地址，第三个地址为添加水印后视频文件地址
        final String text = "ffmpeg -y -i /storage/emulated/0/221.mp4 -i /storage/emulated/0/c3.png -filter_complex [0:v]scale=iw:ih[outv0];[1:0]scale=0.0:0.0[outv1];[outv0][outv1]overlay=0:200 -preset superfast /storage/emulated/0/1/225.mp4";
        String[] commands = text.split(" ");
        myRxFFmpegSubscriber = new MyRxFFmpegSubscriber(this);
        //开始执行FFmpeg命令
        RxFFmpegInvoke.getInstance().runCommandRxJava(commands).subscribe(myRxFFmpegSubscriber);
    }
    /**
     * 这里设为静态内部类，防止内存泄露
     */
    public static class MyRxFFmpegSubscriber extends RxFFmpegSubscriber {

        private WeakReference<HomeFragment> mWeakReference;
        public MyRxFFmpegSubscriber(HomeFragment homeFragment) {
            mWeakReference = new WeakReference<>(homeFragment);
        }
        @Override
        public void onFinish() {
            final HomeFragment mHomeFragment = mWeakReference.get();
            if (mHomeFragment != null) {
                mHomeFragment.cancelProgressDialog("处理成功");
            }
        }
        @Override
        public void onProgress(int progress, long progressTime) {
            final HomeFragment mHomeFragment = mWeakReference.get();
            if (mHomeFragment != null) {
                //progressTime 可以在结合视频总时长去计算合适的进度值
                mHomeFragment.setProgressDialog(progress, progressTime);
            }
        }
        @Override
        public void onCancel() {
            final HomeFragment mHomeFragment = mWeakReference.get();
            if (mHomeFragment != null) {
                mHomeFragment.cancelProgressDialog("已取消");
            }
        }
        @Override
        public void onError(String message) {
            final HomeFragment mHomeFragment = mWeakReference.get();
            if (mHomeFragment != null) {
                mHomeFragment.cancelProgressDialog("出错了 onError：" + message);
            }
        }
    }

最后贴上GitHub地址：https://github.com/Roc0323/WatermarkShoot