dist/scripts/vendor.min.js
function updateInkBarStyles () {
    var elements = getElements();

    if (!elements.tabs[ ctrl.selectedIndex ]) {
      angular.element(elements.inkBar).css({ left: 'auto', right: 'auto' });
      return;
    }

    if (!ctrl.tabs.length) return queue.push(ctrl.updateInkBarStyles);
    // if the element is not visible, we will not be able to calculate sizes until it is
    // we should treat that as a resize event rather than just updating the ink bar
    if (!$element.prop('offsetParent')) return handleResizeWhenVisible();

    var index      = ctrl.selectedIndex,
        totalWidth = elements.paging.offsetWidth,
        tab        = elements.tabs[ index ],
        left       = tab.offsetLeft,
        right      = totalWidth - left - tab.offsetWidth;

    if (ctrl.shouldCenterTabs) {
      // We need to use the same calculate process as in the pagination wrapper, to avoid rounding deviations.
      var tabWidth = calcTabsWidth(elements.tabs);

      if (totalWidth > tabWidth) {
        $mdUtil.nextTick(updateInkBarStyles, false);
      }
    }
    updateInkBarClassName();
    angular.element(elements.inkBar).css({ left: left + 'px', right: right + 'px' });
  }
function updateInkBarStyles () {
    var elements = getElements();

    if (!elements.tabs[ ctrl.selectedIndex ]) {
      angular.element(elements.inkBar).css({ left: 'auto', right: 'auto' });
      return;
    }

    if (!ctrl.tabs.length) return queue.push(ctrl.updateInkBarStyles);
    // if the element is not visible, we will not be able to calculate sizes until it is
    // we should treat that as a resize event rather than just updating the ink bar
    if (!$element.prop('offsetParent')) return handleResizeWhenVisible();

    var index      = ctrl.selectedIndex,
        totalWidth = elements.paging.offsetWidth,
        tab        = elements.tabs[ index ],
        left       = tab.offsetLeft,
        right      = totalWidth - left - tab.offsetWidth;

    if (ctrl.shouldCenterTabs) {
      // We need to use the same calculate process as in the pagination wrapper, to avoid rounding deviations.
      var tabWidth = calcTabsWidth(elements.tabs);

      if (totalWidth > tabWidth) {
        $mdUtil.nextTick(updateInkBarStyles, false);
      }
    }
    updateInkBarClassName();
    angular.element(elements.inkBar).css({ left: left + 'px', right: right + 'px' });
  }
Repositions the ink bar to the selected tab.
@returns {*}