Cacher is the code snippet organizer for pro developers

 public class RoundedTransformation implements com.squareup.picasso.Transformation {
        private final int radius;
        private final int margin;  // dp

        // radius is corner radii in dp
        // margin is the board in dp
        public RoundedTransformation(final int radius, final int margin) {
            this.radius = radius;
            this.margin = margin;
        }

        @Override
        public Bitmap transform(final Bitmap source) {
            int size = Math.min(source.getWidth(), source.getHeight());

            int x = (source.getWidth() - size) / 2;
            int y = (source.getHeight() - size) / 2;

            Bitmap squaredBitmap = Bitmap.createBitmap(source, x, y, size, size);
            if (squaredBitmap != source) {
                source.recycle();
            }

            Bitmap bitmap = Bitmap.createBitmap(size, size, source.getConfig());

            Canvas canvas = new Canvas(bitmap);
            Paint paint = new Paint();
            BitmapShader shader = new BitmapShader(squaredBitmap,
                    BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
            paint.setShader(shader);
            paint.setAntiAlias(true);

            float r = size / 2f;
            canvas.drawCircle(r, r, r, paint);

            squaredBitmap.recycle();
            return bitmap;
        }

        @Override
        public String key() {
            return "rounded " + Calendar.getInstance().getTimeInMillis();
        }
    }
    
  //Usage
  Picasso.with(mContext).load(mPicFile).transform(new RoundedTransformation(mUserPhoto.getMeasuredWidth(), 10)).into(mUserPhoto);