How to rotate an object through corner points?

Question

Canvas

Good afternoon.
I am using canvas and fabric.js library. The question is how to make it possible to rotate an object not through a point above the object, which is enabled by the hasRotatingPoint:false property, but through corner points.
My example is here.
jsfiddle.net/fix2015/BCYBZ/1
Maybe, to make the question clearer, I'll rephrase how to change the pivot point, from the top to all the side ones.

Answer 1

I found an example on the site fbcover-designer.com in the text section, well, it's not clear how they did it.