demos/Collage/fabric.js
function (x, y) {

      var t = this._currentTransform,
          o = this._offset;

      if (t.target.lockRotation) return;

      var lastAngle = atan2(t.ey - t.top - o.top, t.ex - t.left - o.left),
          curAngle = atan2(y - t.top - o.top, x - t.left - o.left);

      t.target._theta = (curAngle - lastAngle) + t.theta;
    }
function (x, y) {

      var t = this._currentTransform,
          o = this._offset;

      if (t.target.lockRotation) return;

      var lastAngle = atan2(t.ey - t.top - o.top, t.ex - t.left - o.left),
          curAngle = atan2(y - t.top - o.top, x - t.left - o.left);

      t.target._theta = (curAngle - lastAngle) + t.theta;
    }
function ( x , y ) { var t = this . _currentTransform , o = this . _offset ; if ( t . target . lockRotation ) return ; var lastAngle = atan2 ( t . ey - t . top - o . top , t . ex - t . left - o . left ) , curAngle = atan2 ( y - t . top - o . top , x - t . left - o . left ) ; t . target . _theta = ( curAngle - lastAngle ) + t . theta ; }
Rotates object by invoking its rotate method
@method _rotateObject
@param x {Number} pointer's x coordinate
@param y {Number} pointer's y coordinate
Rotates object by invoking its rotate method