bounding rect zoom and pan compensation

        
function getZoomCompensatedBoundingRect(fabricObject){
  //fabricObject is the object you want to get the boundingRect from
  fabricObject.setCoords();
  var boundingRect = fabricObject.getBoundingRect();
  var zoom = canvas.getZoom();
  var viewportMatrix = canvas.viewportTransform;
  
  //there is a bug in fabric that causes bounding rects to not be transformed by viewport matrix
  //this code should compensate for the bug for now
  
  boundingRect.top = (boundingRect.top - viewportMatrix[5]) / zoom;
  boundingRect.left = (boundingRect.left - viewportMatrix[4]) / zoom;
  boundingRect.width /= zoom;
  boundingRect.height /= zoom;
  
  return boundingRect;

}