Bitmap is cropped wrong in onPictureTaken

Question

I want to implement my own face detection/recognition android app. When camera finds some face, a rectangle is displayed on camera preview (in real time). App has method for taking photos too. However, I dont want to save whole picture, only the area within the rectangle - the human face. When I give the rectangle coordinates to Bitmap.createBitmap method to crop my picture, correctness of cropped photo depends on the place on display, where the rectangle was shown. When a detected face appears in the middle of preview, createBitmap crops it circa fine, but not if it shows on left or right side of the display. Seems like the coordinates I send to Bitmap.createBitmap are conversed but I cannot find the ratio. Any solutions?

• Here is my onPictureTaken method:

   @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());
      }
  }
  

and here is some example of cropped picture, I do not have enough reputation to post more links:

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

(sorry about making picture of picture, I was lazy to implement saving the rectangle together with photo)

Answer 1

Resolved

The solution was very simple - because of using frontal camera the captured image was always reflected, added two if-clauses:

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();