public void setAspectRatioX(int aspectRatioX) {
    if (aspectRatioX <= 0) {
      throw new IllegalArgumentException(
          "Cannot set aspect ratio value to a number less than or equal to 0.");
    } else if (mAspectRatioX != aspectRatioX) {
      mAspectRatioX = aspectRatioX;
      mTargetAspectRatio = ((float) mAspectRatioX) / mAspectRatioY;

      if (initializedCropWindow) {
        initCropWindow();
        invalidate();
      }
    }
  }
Sets the X value of the aspect ratio; is defaulted to 1.
core/src/main/java/com/theartofdev/edmodo/cropper/CropOverlayView.java