<?php
  /**
   * DOMPDF - PHP5 HTML to PDF renderer
   *
   * File: $RCSfile: page_frame_reflower.cls.php,v $
   * Created on: 2004-06-16
   *
   * Copyright (c) 2004 - Benj Carson <benjcarson@digitaljunkies.ca>
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with this library in the file LICENSE.LGPL; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   * 02111-1307 USA
   *
   * Alternatively, you may distribute this software under the terms of the
   * PHP License, version 3.0 or later.  A copy of this license should have
   * been distributed with this file in the file LICENSE.PHP .  If this is not
   * the case, you can obtain a copy at http://www.php.net/license/3_0.txt.
   *
   * The latest version of DOMPDF might be available at:
   * http://www.dompdf.com/
   *
   * @link http://www.dompdf.com/
   * @copyright 2004 Benj Carson
   * @author Benj Carson <benjcarson@digitaljunkies.ca>
   * @package dompdf
  
   */
  
  /* $Id: page_frame_reflower.cls.php 357 2011-01-30 20:56:46Z fabien.menager $ */
  
  /**
   * Reflows pages
   *
   * @access private
   * @package dompdf
   */
  class Page_Frame_Reflower extends Frame_Reflower {
  
    /**
     * Cache of the callbacks array
     * 
     * @var array
     */
    private $_callbacks;
    
    /**
     * Cache of the canvas
     *
     * @var Canvas
     */
    private $_canvas;
    
    /**
     * This page's floating frames
     * 
     * @var array
     */
    private $_floating_frames;
    
    /**
     * true if the page has floating frales
     * Used to improve performances as it will
     * be accesses everytime
     * @var bool
     */
    private $_has_floating_frames;
    
    /**
     * The stacking context, containing all z-indexed frames
     * @var array
     */
    private $_stacking_context = array();
  
    function __construct(Page_Frame_Decorator $frame) { parent::__construct($frame); }
    
    /**
     * @return array
     */
    function get_floating_frames() { return $this->_floating_frames; }
  
    /**
     * @param $frame Frame
     * @return void
     */
    function add_frame_to_stacking_context(Frame $frame, $z_index) {
      $this->_stacking_context[$z_index][] = $frame;
    }
    
    /**
     * Add a floating frame
     * 
     * @param $child Frame
     */
    function add_floating_frame(Frame $frame) {
      $this->_floating_frames[] = $frame;
      $this->_has_floating_frames = true;
    }
    
    /**
     * Tells if the page has floating frames
     * 
     * @return bool 
     */
    function has_floating_frames() {
      return $this->_has_floating_frames;
    }
    
    //........................................................................
  
    function reflow(Frame_Decorator $block = null) {
      $style = $this->_frame->get_style();
      
      // Paged layout:
      // http://www.w3.org/TR/CSS21/page.html
  
      // Pages are only concerned with margins
      $cb = $this->_frame->get_containing_block();
      $left   = $style->length_in_pt($style->margin_left,   $cb["w"]);
      $right  = $style->length_in_pt($style->margin_right,  $cb["w"]);
      $top    = $style->length_in_pt($style->margin_top,    $cb["h"]);
      $bottom = $style->length_in_pt($style->margin_bottom, $cb["h"]);
      
      $content_x = $cb["x"] + $left;
      $content_y = $cb["y"] + $top;
      $content_width = $cb["w"] - $left - $right;
      $content_height = $cb["h"] - $top - $bottom;
      
      $fixed_children = array();
      
      $prev_child = null;
      $child = $this->_frame->get_first_child();
      $current_page = 0;
  		
      while ($child) {
        // Only if it's the first page, we save the nodes with a fixed position
        if ($current_page == 0) {
          $children = $child->get_children();
          foreach ($children as $onechild) {
            if ($onechild->get_style()->position === "fixed") {
              $fixed_children[] = $onechild->deep_copy();
            }
          }
          $fixed_children = array_reverse($fixed_children);
        }
        
        $child->set_containing_block($content_x, $content_y, $content_width, $content_height);
        
        // Check for begin reflow callback
        $this->_check_callbacks("begin_page_reflow", $child);
      
        //Insert a copy of each node which have a fixed position
        if ($current_page >= 1) {
          foreach ($fixed_children as $fixed_child) {
            $child->insert_child_before($fixed_child->deep_copy(), $child->get_first_child());
          }
        }
        
        $child->reflow();
        $next_child = $child->get_next_sibling();
        
        // Check for begin render callback
        $this->_check_callbacks("begin_page_render", $child);
        
        $renderer = $this->_frame->get_renderer();
  
        // Render the page
        $renderer->render($child);
        
        // http://www.w3.org/TR/CSS21/visuren.html#z-index
        ksort($this->_stacking_context);
        
        foreach( $this->_stacking_context as $_z_index => $_frames ) {
          foreach ( $_frames as $_frame ) {
            $renderer->render($_frame);
          }
        }
        
        $this->_stacking_context = array();
        
        // Check for end render callback
        $this->_check_callbacks("end_page_render", $child);
        
        if ( $next_child ) {
          $this->_frame->next_page();
        }
  
        // Wait to dispose of all frames on the previous page
        // so callback will have access to them
        if ( $prev_child ) {
          $prev_child->dispose(true);
        }
        $prev_child = $child;
        $child = $next_child;
        $current_page++;
      }
  
      // Dispose of previous page if it still exists
      if ( $prev_child ) {
        $prev_child->dispose(true);
      }
    }  
    
    //........................................................................
    
    /**
     * Check for callbacks that need to be performed when a given event
     * gets triggered on a page
     *
     * @param string $event the type of event
     * @param Frame $frame the frame that event is triggered on
     */
    protected function _check_callbacks($event, $frame) {
      if (!isset($this->_callbacks)) {
        $dompdf = $this->_frame->get_dompdf();
        $this->_callbacks = $dompdf->get_callbacks();
        $this->_canvas = $dompdf->get_canvas();
      }
      
      if (is_array($this->_callbacks) && isset($this->_callbacks[$event])) {
        $info = array(0 => $this->_canvas, "canvas" => $this->_canvas,
                      1 => $frame, "frame" => $frame);
        $fs = $this->_callbacks[$event];
        foreach ($fs as $f) {
          if (is_callable($f)) {
            if (is_array($f)) {
              $f[0]->$f[1]($info);
            } else {
              $f($info);
            }
          }
        }
      }
    }  
  }