docs: private RectF getDisplayRect(Matrix matrix) {
          Drawable d = mImageView.getDrawable();
          if (d != null) {
              mDisplayRect.set(0, 0, d.getIntrinsicWidth(),
                  d.getIntrinsicHeight());
              matrix.mapRect(mDisplayRect);
              return mDisplayRect;
          }
          return null;
      }