title: Trigger a function in a child directive from it's parent [angularJS]
body: <p>So I totally do this in reverse all the time when using the directive property <code>require: '^ParentCtrl'</code> inside the child directive.  Using require to then call the parent function; however, I need to do this in reverse.  </p>
  
  <p><strong>Question:</strong><br>
  How do I trigger FROM a parent directive the execution of a function IN a child directive. </p>
  
  <p>Note: 
  1.  Child Directive has no  function is inside a <code>link:</code>
  2.  essentially I want a reverse require.</p>
  
  <p><strong>Parent Directive:</strong></p>
  
  <pre><code>'use strict';
  angular.module('carouselApp')
    .directive('waCarousel', function() {
      return {
          templateUrl: 'views/carousel/wa.carousel.html',
          controller: function($scope) {
              var self = this;
              // this function is being called based on how many pages there are
              self.carouselElLoaded = function(result) {
                  var count = 1;
                  Carousel.params.pageRenderedLength += count;
                  //when all the pages are loaded
                  if (Carousel.params.pageRenderedLength === Carousel.params.pageLength) {
                      Carousel.params.carouselReady = true;
                      // !!!!!!!! Trigger will go here!!!!!!!!!//
                      ChildCtrl.drawHotspots(); // (**for placement only**)
                  } else {
                      Carousel.params.carouselReady = false;
                  }
  
              };
          }
      }
  })
  </code></pre>
  
  <p><strong>Child Directive:</strong></p>
  
  <pre><code>'use strict';
  angular.module('carouselApp')
    .directive('waHotspots', function() {
      return {
          require: '^waCarousel',
          link: function (scope, element, attrs, ctrl) {
                //call this directive based on how
                scope.drawHotspots = function () {...};
          }
      })
  </code></pre>