1 | <?php |
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2 | /** |
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3 | * DOMPDF - PHP5 HTML to PDF renderer |
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4 | * |
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5 | * File: $RCSfile: page_frame_decorator.cls.php,v $ |
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6 | * Created on: 2004-06-15 |
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7 | * |
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8 | * Copyright (c) 2004 - Benj Carson <benjcarson@digitaljunkies.ca> |
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9 | * |
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10 | * This library is free software; you can redistribute it and/or |
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11 | * modify it under the terms of the GNU Lesser General Public |
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12 | * License as published by the Free Software Foundation; either |
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13 | * version 2.1 of the License, or (at your option) any later version. |
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14 | * |
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15 | * This library is distributed in the hope that it will be useful, |
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16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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18 | * Lesser General Public License for more details. |
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19 | * |
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20 | * You should have received a copy of the GNU Lesser General Public License |
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21 | * along with this library in the file LICENSE.LGPL; if not, write to the |
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22 | * Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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23 | * 02111-1307 USA |
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24 | * |
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25 | * Alternatively, you may distribute this software under the terms of the |
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26 | * PHP License, version 3.0 or later. A copy of this license should have |
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27 | * been distributed with this file in the file LICENSE.PHP . If this is not |
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28 | * the case, you can obtain a copy at http://www.php.net/license/3_0.txt. |
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29 | * |
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30 | * The latest version of DOMPDF might be available at: |
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31 | * http://www.digitaljunkies.ca/dompdf |
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32 | * |
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33 | * @link http://www.digitaljunkies.ca/dompdf |
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34 | * @copyright 2004 Benj Carson |
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35 | * @author Benj Carson <benjcarson@digitaljunkies.ca> |
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36 | * @package dompdf |
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37 | * @version 0.5.1 |
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38 | */ |
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39 | |
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40 | /* $Id: page_frame_decorator.cls.php,v 1.13 2006/07/07 21:31:04 benjcarson Exp $ */ |
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41 | |
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42 | /** |
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43 | * Decorates frames for page layout |
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44 | * |
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45 | * @access private |
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46 | * @package dompdf |
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47 | */ |
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48 | class Page_Frame_Decorator extends Frame_Decorator { |
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49 | |
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50 | /** |
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51 | * y value of bottom page margin |
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52 | * |
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53 | * @var float |
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54 | */ |
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55 | protected $_bottom_page_margin; |
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56 | |
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57 | /** |
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58 | * Flag indicating page is full. |
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59 | * |
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60 | * @var bool |
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61 | */ |
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62 | protected $_page_full; |
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63 | |
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64 | /** |
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65 | * Number of tables currently being reflowed |
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66 | * |
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67 | * @var int |
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68 | */ |
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69 | protected $_in_table; |
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70 | |
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71 | /** |
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72 | * The pdf renderer |
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73 | * |
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74 | * @var Renderer |
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75 | */ |
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76 | protected $_renderer; |
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77 | |
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78 | //........................................................................ |
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79 | |
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80 | /** |
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81 | * Class constructor |
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82 | * |
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83 | * @param Frame $frame the frame to decorate |
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84 | */ |
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85 | function __construct(Frame $frame, DOMPDF $dompdf) { |
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86 | parent::__construct($frame, $dompdf); |
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87 | $this->_page_full = false; |
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88 | $this->_in_table = 0; |
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89 | $this->_bottom_page_margin = null; |
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90 | } |
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91 | |
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92 | |
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93 | /** |
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94 | * Set the renderer used for this pdf |
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95 | * |
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96 | * @param Renderer $renderer the renderer to use |
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97 | */ |
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98 | function set_renderer($renderer) { |
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99 | $this->_renderer = $renderer; |
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100 | } |
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101 | |
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102 | /** |
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103 | * Return the renderer used for this pdf |
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104 | * |
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105 | * @return Renderer |
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106 | */ |
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107 | function get_renderer() { |
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108 | return $this->_renderer; |
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109 | } |
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110 | |
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111 | /** |
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112 | * Set the frame's containing block. Overridden to set $this->_bottom_page_margin. |
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113 | * |
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114 | * @param float $x |
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115 | * @param float $y |
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116 | * @param float $w |
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117 | * @param float $h |
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118 | */ |
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119 | function set_containing_block($x = null, $y = null, $w = null, $h = null) { |
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120 | parent::set_containing_block($x,$y,$w,$h); |
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121 | $w = $this->get_containing_block("w"); |
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122 | if ( isset($h) ) |
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123 | $this->_bottom_page_margin = $h; // - $this->_frame->get_style()->length_in_pt($this->_frame->get_style()->margin_bottom, $w); |
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124 | } |
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125 | |
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126 | /** |
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127 | * Returns true if the page is full and is no longer accepting frames. |
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128 | * |
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129 | * @return bool |
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130 | */ |
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131 | function is_full() { |
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132 | return $this->_page_full; |
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133 | } |
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134 | |
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135 | /** |
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136 | * Start a new page by resetting the full flag. |
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137 | */ |
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138 | function next_page() { |
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139 | $this->_renderer->new_page(); |
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140 | $this->_page_full = false; |
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141 | } |
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142 | |
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143 | /** |
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144 | * Indicate to the page that a table is currently being reflowed. |
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145 | */ |
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146 | function table_reflow_start() { |
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147 | $this->_in_table++; |
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148 | } |
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149 | |
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150 | /** |
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151 | * Indicate to the page that table reflow is finished. |
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152 | */ |
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153 | function table_reflow_end() { |
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154 | $this->_in_table--; |
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155 | } |
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156 | |
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157 | /** |
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158 | * Check if a forced page break is required before $frame. This uses the |
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159 | * frame's page_break_before property as well as the preceeding frame's |
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160 | * page_break_after property. |
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161 | * |
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162 | * @link http://www.w3.org/TR/CSS21/page.html#forced |
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163 | * |
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164 | * @param Frame $frame the frame to check |
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165 | * @return bool true if a page break occured |
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166 | */ |
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167 | function check_forced_page_break(Frame $frame) { |
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168 | |
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169 | // Skip check if page is already split |
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170 | if ( $this->_page_full ) |
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171 | return; |
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172 | |
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173 | $block_types = array("block", "list-item", "table"); |
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174 | $page_breaks = array("always", "left", "right"); |
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175 | |
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176 | $style = $frame->get_style(); |
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177 | |
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178 | if ( !in_array($style->display, $block_types) ) |
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179 | return false; |
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180 | |
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181 | // Find the previous block-level sibling |
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182 | $prev = $frame->get_prev_sibling(); |
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183 | while ( $prev && !in_array($prev->get_style()->display, $block_types) ) |
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184 | $prev = $prev->get_prev_sibling(); |
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185 | |
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186 | if ( in_array($style->page_break_before, $page_breaks) ) { |
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187 | |
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188 | // Prevent cascading splits |
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189 | $frame->split(); |
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190 | // We have to grab the style again here because split() resets |
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191 | // $frame->style to the frame's orignal style. |
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192 | $frame->get_style()->page_break_before = "auto"; |
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193 | $this->_page_full = true; |
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194 | return true; |
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195 | } |
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196 | |
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197 | if ( ($prev && in_array($prev->get_style()->page_break_after, $page_breaks)) ) { |
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198 | // Prevent cascading splits |
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199 | $frame->split(); |
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200 | $prev->get_style()->page_break_after = "auto"; |
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201 | $this->_page_full = true; |
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202 | return true; |
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203 | } |
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204 | |
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205 | return false; |
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206 | } |
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207 | |
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208 | /** |
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209 | * Determine if a page break is allowed before $frame |
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210 | * |
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211 | * @param Frame $frame the frame to check |
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212 | * @return bool true if a break is allowed, false otherwise |
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213 | */ |
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214 | protected function _page_break_allowed(Frame $frame) { |
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215 | /** |
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216 | * |
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217 | * http://www.w3.org/TR/CSS21/page.html#allowed-page-breaks |
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218 | * /* |
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219 | * In the normal flow, page breaks can occur at the following places: |
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220 | * |
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221 | * 1. In the vertical margin between block boxes. When a page |
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222 | * break occurs here, the used values of the relevant |
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223 | * 'margin-top' and 'margin-bottom' properties are set to '0'. |
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224 | * 2. Between line boxes inside a block box. |
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225 | * |
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226 | * These breaks are subject to the following rules: |
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227 | * |
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228 | * * Rule A: Breaking at (1) is allowed only if the |
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229 | * 'page-break-after' and 'page-break-before' properties of |
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230 | * all the elements generating boxes that meet at this margin |
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231 | * allow it, which is when at least one of them has the value |
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232 | * 'always', 'left', or 'right', or when all of them are |
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233 | * 'auto'. |
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234 | * |
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235 | * * Rule B: However, if all of them are 'auto' and the |
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236 | * nearest common ancestor of all the elements has a |
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237 | * 'page-break-inside' value of 'avoid', then breaking here is |
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238 | * not allowed. |
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239 | * |
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240 | * * Rule C: Breaking at (2) is allowed only if the number of |
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241 | * line boxes between the break and the start of the enclosing |
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242 | * block box is the value of 'orphans' or more, and the number |
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243 | * of line boxes between the break and the end of the box is |
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244 | * the value of 'widows' or more. |
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245 | * |
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246 | * * Rule D: In addition, breaking at (2) is allowed only if |
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247 | * the 'page-break-inside' property is 'auto'. |
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248 | * |
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249 | * If the above doesn't provide enough break points to keep |
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250 | * content from overflowing the page boxes, then rules B and D are |
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251 | * dropped in order to find additional breakpoints. |
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252 | * |
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253 | * If that still does not lead to sufficient break points, rules A |
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254 | * and C are dropped as well, to find still more break points. |
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255 | * |
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256 | * [endquote] |
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257 | * |
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258 | * We will also allow breaks between table rows. However, when |
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259 | * splitting a table, the table headers should carry over to the |
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260 | * next page (but they don't yet). |
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261 | */ |
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262 | |
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263 | $block_types = array("block", "list-item", "table"); |
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264 | // echo "\nbreak_allowed: " . $frame->get_node()->nodeName ."\n"; |
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265 | $display = $frame->get_style()->display; |
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266 | |
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267 | // Block Frames (1): |
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268 | if ( in_array($display, $block_types) ) { |
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269 | |
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270 | // Avoid breaks within table-cells |
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271 | if ( $this->_in_table ) { |
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272 | // echo "In table: " . $this->_in_table ."\n"; |
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273 | return false; |
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274 | } |
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275 | |
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276 | // Rules A & B |
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277 | |
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278 | if ( $frame->get_style()->page_break_before == "avoid" ) { |
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279 | // echo "before: avoid\n"; |
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280 | return false; |
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281 | } |
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282 | |
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283 | // Find the preceeding block-level sibling |
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284 | $prev = $frame->get_prev_sibling(); |
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285 | while ( $prev && !in_array($prev->get_style()->display, $block_types) ) |
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286 | $prev = $prev->get_prev_sibling(); |
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287 | |
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288 | // Does the previous element allow a page break after? |
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289 | if ( $prev && $prev->get_style()->page_break_after == "avoid" ) { |
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290 | // echo "after: avoid\n"; |
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291 | return false; |
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292 | } |
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293 | |
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294 | // If both $prev & $frame have the same parent, check the parent's |
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295 | // page_break_inside property. |
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296 | $parent = $frame->get_parent(); |
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297 | if ( $prev && $parent && $parent->get_style()->page_break_inside == "avoid" ) { |
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298 | // echo "parent inside: avoid\n"; |
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299 | return false; |
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300 | } |
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301 | |
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302 | // To prevent cascading page breaks when a top-level element has |
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303 | // page-break-inside: avoid, ensure that at least one frame is |
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304 | // on the page before splitting. |
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305 | if ( $parent->get_node()->nodeName == "body" && !$prev ) { |
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306 | // We are the body's first child |
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307 | // echo "Body's first child.\n"; |
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308 | return false; |
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309 | } |
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310 | |
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311 | // If the frame is the first block-level frame, use the value from |
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312 | // $frame's parent instead. |
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313 | if ( !$prev && $parent ) |
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314 | return $this->_page_break_allowed( $parent ); |
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315 | |
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316 | // echo "block: break allowed\n"; |
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317 | return true; |
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318 | |
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319 | } |
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320 | |
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321 | // Inline frames (2): |
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322 | else if ( in_array($display, Style::$INLINE_TYPES) ) { |
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323 | |
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324 | // Avoid breaks within table-cells |
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325 | if ( $this->_in_table ) { |
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326 | // echo "In table: " . $this->_in_table ."\n"; |
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327 | return false; |
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328 | } |
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329 | |
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330 | // Rule C |
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331 | $block_parent = $frame->find_block_parent(); |
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332 | if ( count($block_parent->get_lines() ) < $frame->get_style()->orphans ) { |
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333 | // echo "orphans\n"; |
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334 | return false; |
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335 | } |
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336 | |
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337 | // FIXME: Checking widows is tricky without having laid out the |
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338 | // remaining line boxes. Just ignore it for now... |
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339 | |
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340 | // Rule D |
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341 | if ( $block_parent->get_style()->page_break_inside == "avoid" ) { |
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342 | // echo "parent->inside: avoid\n"; |
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343 | return false; |
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344 | } |
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345 | |
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346 | // To prevent cascading page breaks when a top-level element has |
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347 | // page-break-inside: avoid, ensure that at least one frame with |
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348 | // some content is on the page before splitting. |
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349 | $prev = $frame->get_prev_sibling(); |
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350 | while ( $prev && ($prev->get_node()->nodeName == "#text" && trim($prev->get_node()->nodeValue) == "") ) |
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351 | $prev = $prev->get_prev_sibling(); |
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352 | |
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353 | if ( $block_parent->get_node()->nodeName == "body" && !$prev ) { |
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354 | // We are the body's first child |
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355 | // echo "Body's first child.\n"; |
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356 | return false; |
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357 | } |
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358 | |
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359 | // Skip breaks on empty text nodes |
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360 | if ( $frame->get_node()->nodeName == "#text" && |
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361 | $frame->get_node()->nodeValue == "" ) |
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362 | return false; |
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363 | |
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364 | // echo "inline: break allowed\n"; |
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365 | return true; |
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366 | |
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367 | // Table-rows |
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368 | } else if ( $display == "table-row" ) { |
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369 | |
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370 | // Simply check if the parent table's page_break_inside property is |
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371 | // not 'avoid' |
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372 | $p = Table_Frame_Decorator::find_parent_table($frame); |
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373 | |
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374 | if ( $p->get_style()->page_break_inside == "avoid" ) { |
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375 | // echo "table: page-break-inside: avoid\n"; |
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376 | return false; |
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377 | } |
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378 | |
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379 | // Check the table's parent element |
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380 | $table_parent = $p->get_parent(); |
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381 | |
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382 | if ( $table_parent->get_style()->page_break_inside == "avoid" ) { |
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383 | // echo "table->parent: page-break-inside: avoid\n"; |
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384 | return false; |
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385 | } |
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386 | |
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387 | // Avoid breaking after the first row of a table |
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388 | if ( $p->get_first_child() === $frame) { |
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389 | // echo "table: first-row\n"; |
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390 | return false; |
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391 | } |
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392 | |
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393 | // echo "table-row/row-groups: break allowed\n"; |
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394 | return true; |
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395 | |
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396 | } else if ( in_array($display, Table_Frame_Decorator::$ROW_GROUPS) ) { |
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397 | |
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398 | // Disallow breaks at row-groups: only split at row boundaries |
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399 | return false; |
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400 | |
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401 | } else { |
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402 | |
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403 | // echo "? " . $frame->get_style()->display . "\n"; |
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404 | return false; |
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405 | } |
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406 | |
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407 | } |
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408 | |
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409 | /** |
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410 | * Check if $frame will fit on the page. If the frame does not fit, |
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411 | * the frame tree is modified so that a page break occurs in the |
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412 | * correct location. |
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413 | * |
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414 | * @param Frame $frame the frame to check |
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415 | * @return Frame the frame following the page break |
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416 | */ |
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417 | function check_page_break(Frame $frame) { |
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418 | // Do not split if we have already |
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419 | if ( $this->_page_full ) |
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420 | return false; |
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421 | |
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422 | // Determine the frame's maximum y value |
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423 | $max_y = $frame->get_position("y") + $frame->get_margin_height(); |
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424 | |
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425 | // If a split is to occur here, then the bottom margins & paddings of all |
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426 | // parents of $frame must fit on the page as well: |
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427 | $p = $frame->get_parent(); |
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428 | while ( $p ) { |
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429 | $style = $p->get_style(); |
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430 | $max_y += $style->length_in_pt(array($style->margin_bottom, |
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431 | $style->padding_bottom, |
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432 | $style->border_bottom_width)); |
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433 | $p = $p->get_parent(); |
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434 | } |
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435 | |
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436 | |
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437 | // Check if $frame flows off the page |
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438 | if ( $max_y <= $this->_bottom_page_margin ) |
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439 | // no: do nothing (?) |
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440 | return false; |
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441 | |
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442 | // echo "check_page_break\n"; |
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443 | |
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444 | // yes: determine page break location |
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445 | $iter = $frame; |
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446 | $flg = false; |
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447 | |
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448 | $in_table = $this->_in_table; |
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449 | |
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450 | // echo "Starting search\n"; |
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451 | while ( $iter ) { |
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452 | // echo "\nbacktrack: " .$iter->get_node()->nodeName ." ".(string)$iter->get_node(). "\n"; |
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453 | if ( $iter === $this ) { |
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454 | // echo "reached root.\n"; |
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455 | // We've reached the root in our search. Just split at $frame. |
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456 | break; |
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457 | } |
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458 | |
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459 | if ( $this->_page_break_allowed($iter) ) { |
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460 | // echo "break allowed, splitting.\n"; |
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461 | $iter->split(); |
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462 | $this->_page_full = true; |
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463 | $this->_in_table = $in_table; |
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464 | return true; |
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465 | } |
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466 | |
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467 | if ( !$flg && $next = $iter->get_last_child() ) { |
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468 | // echo "following last child.\n"; |
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469 | |
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470 | if ( in_array($next->get_style()->display, Style::$TABLE_TYPES) ) |
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471 | $this->_in_table++; |
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472 | |
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473 | $iter = $next; |
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474 | continue; |
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475 | } |
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476 | |
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477 | if ( $next = $iter->get_prev_sibling() ) { |
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478 | // echo "following prev sibling.\n"; |
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479 | |
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480 | if ( in_array($next->get_style()->display, Style::$TABLE_TYPES) && |
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481 | !in_array($iter->get_style()->display, Style::$TABLE_TYPES) ) |
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482 | $this->_in_table++; |
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483 | |
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484 | else if ( !in_array($next->get_style()->display, Style::$TABLE_TYPES) && |
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485 | in_array($iter->get_style()->display, Style::$TABLE_TYPES) ) |
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486 | $this->_in_table--; |
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487 | |
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488 | $iter = $next; |
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489 | $flg = false; |
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490 | continue; |
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491 | } |
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492 | |
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493 | if ( $next = $iter->get_parent() ) { |
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494 | // echo "following parent.\n"; |
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495 | |
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496 | if ( in_array($iter->get_style()->display, Style::$TABLE_TYPES) ) |
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497 | $this->_in_table--; |
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498 | |
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499 | $iter = $next; |
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500 | $flg = true; |
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501 | continue; |
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502 | } |
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503 | |
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504 | break; |
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505 | |
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506 | } |
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507 | |
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508 | $this->_in_table = $in_table; |
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509 | |
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510 | // No valid page break found. Just break at $frame. |
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511 | // echo "no valid break found, just splitting.\n"; |
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512 | |
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513 | // If we are in a table, backtrack to the nearest table row |
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514 | if ( $this->_in_table ) { |
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515 | $tr = $frame; |
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516 | while ($tr && $tr->get_style()->display != "table-row" ) |
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517 | $tr = $tr->get_parent(); |
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518 | |
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519 | $tr->split(); |
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520 | $this->_page_full = true; |
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521 | return true; |
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522 | } |
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523 | |
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524 | $frame->split(); |
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525 | $this->_page_full = true; |
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526 | return true; |
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527 | |
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528 | } |
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529 | |
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530 | //........................................................................ |
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531 | |
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532 | function split($frame = null) { |
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533 | // Do nothing |
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534 | } |
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535 | |
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536 | } |
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537 | ?> |
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