android - 位图在 onPictureTaken 中裁剪错误

Question

我想实现自己的人脸检测/识别安卓应用。当相机发现一些人脸时，一个矩形会显示在相机预览中(实时)。应用程序也有拍照的方法。但是，我不想保存整个图片，只保存矩形内的区域 - 人脸。当我将矩形坐标提供给 Bitmap.createBitmap 方法来裁剪图片时，裁剪照片的正确性取决于显示的位置，即显示矩形的位置。当检测到的人脸出现在预览中间时，createBitmap 会裁剪它，但如果它显示在显示屏的左侧或右侧则不会。似乎我发送给 Bitmap.createBitmap 的坐标被转换了，但我找不到比例。任何解决方案？

• 这是我的 onPictureTaken 方法:

   @Override
  public void onPictureTaken(byte[] data, Camera camera) {
  
      File pictureFile = getOutputMediaFile(); 
      if (pictureFile == null) {
          Log.d(TAG, "Error creating media file, check storage permissions: ");
          return;
      }
  
      Bitmap picture = BitmapFactory.decodeByteArray(data, 0, data.length);
      RectF faceRect = mPreview.getFaceRect();
  
  
      float x = faceRect.left;
      float y = faceRect.top;
      float w = faceRect.right - faceRect.left;
      float h = faceRect.bottom - faceRect.top;
  
      int intX = (int) x;
      int intY = (int) y;
      int intW = (int) w;
      int intH = (int) h;
  
      Bitmap croppedPicture = Bitmap.createBitmap(picture, intX, intY, intW, intH);       
      ByteArrayOutputStream stream = new ByteArrayOutputStream();
      croppedPicture.compress(Bitmap.CompressFormat.JPEG, 100, stream);
      byte[] byteArrayFromPicture = stream.toByteArray();
  
      try {
          FileOutputStream fos = new FileOutputStream(pictureFile); 
          fos.write(byteArrayFromPicture);
          //fos.write(data);
          fos.close();
      } catch (FileNotFoundException e) {
          Log.d(TAG, "File not found: " + e.getMessage());
      } catch (IOException e) {
          Log.d(TAG, "Error accessing file: " + e.getMessage());
      }
  }
  

这里是裁剪图片的一些示例，我没有足够的声誉来发布更多链接:

• face close to the left edge of display
• cropped pic1

(不好意思做图片的图片，我懒得把矩形和照片一起保存了)

Answer 1

已解决

解决方案非常简单——因为使用前置摄像头，捕获的图像总是被反射，添加两个 if 子句:

Bitmap picture = BitmapFactory.decodeByteArray(data, 0, data.length);
        RectF faceRect = mPreview.getFaceRect();
        Camera.Parameters parameters  = mCamera.getParameters();
        int picWidth = parameters.getPictureSize().width;

        int intX = 0;
        int intY = (int) faceRect.top;
        int intW = (int) (faceRect.right - faceRect.left);
        int intH = (int) (faceRect.bottom - faceRect.top);

        if(faceRect.left > picWidth / 2) {
            intX = (int) (faceRect.right - (faceRect.right - picWidth / 2) * 2);
        }
        else if(faceRect.left <= picWidth / 2) {
            intX = (int) (picWidth - faceRect.right);
        }

        Bitmap croppedPicture = Bitmap.createBitmap(picture, intX, intY, intW, intH);       
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        croppedPicture.compress(Bitmap.CompressFormat.JPEG, 100, stream);
        byte[] byteArrayFromPicture = stream.toByteArray();