class.LayoutVisitor.php

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<?php
/**
 * wCMF - wemove Content Management Framework
 * Copyright (C) 2005-2014 wemove digital solutions GmbH
 *
 * Licensed under the terms of any of the following licenses 
 * at your choice:
 *
 * - GNU Lesser General Public License (LGPL)
 *   http://www.gnu.org/licenses/lgpl.html
 * - Eclipse Public License (EPL)
 *   http://www.eclipse.org/org/documents/epl-v10.php
 *
 * See the license.txt file distributed with this work for 
 * additional information.
 *
 * $Id: class.LayoutVisitor.php 1462 2014-02-04 23:52:27Z iherwig $
 */
require_once(BASE."wcmf/lib/visitor/class.Visitor.php");
require_once(BASE."wcmf/lib/util/class.Position.php");
/**
 * Some constants describing the map type
 */
define("MAPTYPE_HORIZONTAL", 0);
define("MAPTYPE_VERTICAL",   1);
/**
 * @class LayoutVisitor
 * @ingroup Visitor
 * @brief The LayoutVisitor is used to position a tree of objects on a plane (the objects must implement the getParent()).
 * It uses a simple algorithm that positions the objects on a discrete array with distance 1 so 
 * that all leaves are equal distant from their neighbours.
 * The positions are stored in a map that is provided by the getMap() method.
 *
 * @author      ingo herwig <ingo@wemove.com>
 */
class LayoutVisitor extends Visitor 
{
  var $_map = array();
  
  /**
   * Constructor.
   */
  function LayoutVisitor()
  {
    // set default maptype
    $this->_map["type"] = MAPTYPE_HORIZONTAL;
  } 
  /**
   * Visit the current object in iteration and position it on the map.
   * @param obj A reference to the current object.
   */
  function visit(&$obj)
  {
    $this->_map[$obj->getOID()] = $this->calculatePosition($obj);
  } 
  /**
   * Visit the current object in iteration and position it on the map.
   * @return The object map as assioziative array (key: object Id, value: Position). 
   * map["type"] = MAPTYPE_HORIZONTAL | MAPTYPE_VERTICAL
   */
  function getMap()
  { 
    return $this->_map;
  }
  /**
   * Flip layout (x <-> y).
   */
  function flip()
  { 
    foreach($this->_map as $key => $position)
    {
      $temp = $position->x;
      $position->x = $position->y;
      $position->y = $temp;
      $this->_map[$key] = $position;
    }
    // switch map type
    $this->_map["type"] = 1-$this->_map["type"];
  }
  /**
   * Calculate the object's position using the described algorithm.
   * @attention Internal use only.
   * @param obj A reference to the current object.
   */
  function calculatePosition(&$obj)
  {
          $parent = & $obj->getParent();
          if (!$parent)
          {
                // start here
                $position = new Position(0,0,0);
          }
          else
          {
            $position = new Position(0,0,0);
                $parentPos = $this->_map[$parent->getOID()];
                $position->y = $parentPos->y + 1;
                $position->z = $parentPos->z + 1;
                
                $siblings = $parent->getChildren();
                if ($siblings[0]->getOID() == $obj->getOID())
                {
                $position->x = $parentPos->x;
        }
                else
                {
                        // find leftmost sibling of object
                        for ($i=0;$i<sizeOf($siblings);$i++)
        {
          if ($siblings[$i]->getOID() == $obj->getOID())
          {
            $leftSibling = & $siblings[$i-1];
          }
        }
                        // find x-coordinate of rightmost descendant of leftmost sibling
                        $maxX = 0;
                        $nIter = new NodeIterator($leftSibling);
        while(!($nIter->isEnd()))
                        {
                          $curObject = & $nIter->getCurrentObject();
                          $curPosition = $this->_map[$curObject->getOID()];
                          if ($curPosition->x >= $maxX)
                            $maxX = $curPosition->x;
          $nIter->proceed();
                        }
                $position->x = $maxX+2;
                        // reposition parents
                        while ($parent != null)
                        {
                                $this->_map[$parent->getOID()]->x += 1;
                                $parent = & $parent->getParent();
                        }
                }
        }
        return $position;
        }
}
?>