Cropping an image on rails

I have the following data both in my js file or as a param in rails. Togther there is an image that is to be sent to server, what I want to achieve is to crop the image based on the data such as below. I am not allowed to use gems :) just using ruby/js code if I can manipulate the image already in js side. I am using cropper js which generated the output to me. What should I do to achieve cropping ? {"x":552.697358490566,"y":-72.49509433962258,"width":696.9599999999999,"height":696.9599999999999,"rotate":0,"scaleX":1,"scaleY":1}