Is there any way in which I can get the bounding box of the drawing ? I am looking to create a resized around the exact bounding of the image <img width="300" alt="screen shot 2018-04-01 at 9 17 31 pm" src="https://user-images.githubusercontent.com/12974407/38173029-2d0191ec-35f2-11e8-88a9-166ee6a441d7.png">