text: define(function (require) {
  
      var helper = require('./traversalHelper');
      var eachAfter = helper.eachAfter;
      var eachBefore = helper.eachBefore;
      var layoutHelper = require('./layoutHelper');
      var init = layoutHelper.init;
      var firstWalk = layoutHelper.firstWalk;
      var secondWalk = layoutHelper.secondWalk;
      var sep = layoutHelper.separation;
      var radialCoordinate = layoutHelper.radialCoordinate;
      var getViewRect = layoutHelper.getViewRect;
  
      return function (seriesModel, api) {
  
          var layoutInfo = getViewRect(seriesModel, api);
          seriesModel.layoutInfo = layoutInfo;
  
          var layout = seriesModel.get('layout');
          var width = 0;
          var height = 0;
          var separation = null;
          if (layout === 'radial') {
              width = 2 * Math.PI;
              height = Math.min(layoutInfo.height, layoutInfo.width) / 2;
              separation = sep(function (node1, node2) {
                  return (node1.parentNode === node2.parentNode ? 1 : 2) / node1.depth;
              });
          }
          else {
              width = layoutInfo.width;
              height = layoutInfo.height;
              separation = sep();
          }
  
          var virtualRoot = seriesModel.getData().tree.root;
          var realRoot = virtualRoot.children[0];
          init(virtualRoot);
          eachAfter(realRoot, firstWalk, separation);
          virtualRoot.hierNode.modifier = - realRoot.hierNode.prelim;
          eachBefore(realRoot, secondWalk);
  
          var left = realRoot;
          var right = realRoot;
          var bottom = realRoot;
          eachBefore(realRoot, function (node) {
              var x = node.getLayout().x;
              if (x < left.getLayout().x) {
                  left = node;
              }
              if (x > right.getLayout().x) {
                  right = node;
              }
              if (node.depth > bottom.depth) {
                  bottom = node;
              }
          });
  
          var delta = left === right ? 1 : separation(left, right) / 2;
          var tx = delta - left.getLayout().x;
          var kx = 0;
          var ky = 0;
          var coorX = 0;
          var coorY = 0;
          if (layout === 'radial') {
              kx = width / (right.getLayout().x + delta + tx);
              // here we use (node.depth - 1), bucause the real root's depth is 1
              ky = height/ ((bottom.depth - 1) || 1);
              eachBefore(realRoot, function (node) {
                  coorX = (node.getLayout().x + tx) * kx;
                  coorY = (node.depth - 1) * ky;
                  var finalCoor = radialCoordinate(coorX, coorY);
                  node.setLayout({x: finalCoor.x, y: finalCoor.y, rawX: coorX, rawY: coorY}, true);
              });
          }
          else {
              if (seriesModel.get('orient') === 'horizontal') {
                  ky = height / (right.getLayout().x + delta + tx);
                  kx = width / ((bottom.depth - 1) || 1);
                  eachBefore(realRoot, function (node) {
                      coorY = (node.getLayout().x + tx) * ky;
                      coorX = (node.depth - 1) * kx;
                      node.setLayout({x: coorX, y: coorY}, true);
                  });
              }
              else {
                  kx = width / (right.getLayout().x + delta + tx);
                  ky = height / ((bottom.depth - 1) || 1);
                  eachBefore(realRoot, function (node) {
                      coorX = (node.getLayout().x + tx) * kx;
                      coorY = (node.depth - 1) * ky;
                      node.setLayout({x: coorX, y: coorY}, true);
                  });
              }
          }
      };
  });
  