public void setFixedAspectRatio(boolean fixAspectRatio) {
    if (mFixAspectRatio != fixAspectRatio) {
      mFixAspectRatio = fixAspectRatio;
      if (initializedCropWindow) {
        initCropWindow();
        invalidate();
      }
    }
  }
Sets whether the aspect ratio is fixed or not; true fixes the aspect ratio, while false allows
it to be changed.
core/src/main/java/com/theartofdev/edmodo/cropper/CropOverlayView.java