Rotate camera preview to Portrait Android OpenCV Camera

Question

I am trying to use OpenCV 2.4.3.2 to create a camera app and do some opencv processing. I would like it to be able to have multiple UI orientations, not just Landscape.

Answer 1

I had the same problem trying to implement OpenCV. I was able to fix it by making the following changes to the deliverAndDrawFrame method.

1. Rotate the canvas object

   Canvas canvas = getHolder().lockCanvas();
   // Rotate canvas to 90 degrees
   canvas.rotate(90f, canvas.getWidth()/2, canvas.getHeight()/2);
   

2. Resize the bitmap to fit entire size of canvas before drawing

   // Resize
   Bitmap bitmap = Bitmap.createScaledBitmap(mCacheBitmap, canvas.getHeight(), canvas.getWidth(), true);
   // Use bitmap instead of mCacheBitmap
   canvas.drawBitmap(bitmap, new Rect(0,0,bitmap.getWidth(), bitmap.getHeight()), new Rect(
       (int)((canvas.getWidth() - mScale*bitmap.getWidth()) / 2),
       (int)((canvas.getHeight() - mScale*bitmap.getHeight()) / 2),
       (int)((canvas.getWidth() - mScale*bitmap.getWidth()) / 2 + mScale*bitmap.getWidth()),
       (int）((canvas.getHeight() - mScale*bitmap.getHeight()) / 2 + mScale*bitmap.getHeight()
     )), null);
   
   // Unlock canvas
   getHolder().unlockCanvasAndPost(canvas);